"Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them... [W]e should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols."
-- Karl Popper (The Open Society and Its Enemies, 1962)
I know politics bore you
But I feel like a hypocrite talking to you
And your racist friend"
-- They Might Be Giants (Your Racist Friend, 1990)
Of the infinite number of stupid things to say in the universe, one of the more resilient ones is "if you don't like bigots, that's just another form of bigotry". This is because it is a simple idea with a complex response. And for those interested in muddying the waters between tolerance and intolerance, it's much easier to choose to forget the complicated thing you don't want to hear about.
The question form of the Paradox of Tolerance is this:
"Can a society be said to be tolerant if it is willing to ostracize the intolerant?"
As far as I can tell there are two good answers here:
1. Yes, society seeking to maximize tolerance can only do so by disincentivizing or outlawing certain behaviors. This view relies on the observation that it is not a zero-sum choice between intolerant expression and those who are subjected to it. E.g. there is greater tolerance in allowing a person to walk down the street unharassed than in creating protections for nasty things to yell from a car window. There is greater tolerance in the general comfort of a mixed-demographic block party than in getting on good terms with the fascist ethnonationalist in the corner who's had a few. The path to making as many ideas, actions, and identities tolerated in our society does not involve total abdication from decision-making on what is acceptable.
2. If the scope of "tolerance" can only be defined as the tolerance of individuals, rather than what those individuals do, then the answer is also yes. This is somewhat similar to the idea that God loves all people, but not all the things that people do. In this view, the society is limiting its tolerance only to issues of identity, rather than actions or expressions. That society's tolerance for identities is not infringed upon whatsoever by the punishments that exist for intolerant violations, since there is no such thing as an inherently bigoted person. It would take the successful argument that intolerance is an undeniable piece of identity in order to gain access, and that's just something nobody would take seriously.
The only real ground for the intolerant nature of tolerance is that an absolutely tolerant society where the complete and total spectrum of human identities, activities and expressions are tolerated is either impossible, or that progressives would not like to live in it. This is true, but it also uses what I call the "absolute strawman", whereby a position is impugned for no reason other than failing to be absolute (which few things are claimed as, and very few can be convincingly argued as). Was planning to do a fuller writeup on it, but the short version is that inserting "always", "never" or "absolutely" into ideas you don't like is an easy way to make them shallowly false.
It is also sometimes phrased in the more argumentative form that involves making assertions about "enforcement" of tolerance. I think this is difficult to talk about, because there is no centralized authority for a tolerant society. There is no ministry of tolerance, no body that meets to pass laws and record it all in minutes, but rather it is made up of the individual decisions of millions of people in their interactions with one another. It cannot be said that there is enforcement of tolerance on a societal level, because none of these individuals has unique authority over one another. They are all nominally equals, choosing the ways in which they interact and do not interact with one another. It is imprecise, imperfect, and with different standards from one person to the next, carried out on individual authority and in response to values that are unwritten. There is also no alternative to this (other than some form of totalitarianism, in which humans have no freedom to determine their own behavior) so criticizing it for being flawed fails to rise to the level of social commentary.
Social norms are descended from the standards and boundaries that individuals set with one another regarding their own conduct: if I refuse to engage in a serious conversation with a man just because he's dressed only in a baseball hat and exactly three socks while yelling through a mouthful of crumbs and has a stench that could peel paint off the wall, then I'm entirely within my rights. I have done nothing to the baseball hat wearing community, or the unwashed community, or those who simply enjoy making conversation with thin air at high decibels. If many people feel the same way, then there is a social norm that these things are not considered polite and the average person is not going to put up with it.
This is why the assertion of the intolerance of tolerance is a frustration of individual authority: it is attempting to use the right of the individual (to be bigoted) to usurp the right of the individual (to not put up with bigots). But this is frequently not how these issues appear, instead they are stories where the individual who is transgressing the social norm of tolerance appears as one figure, and the opposing individuals who are all acting of their own volition and right are many and unknown. Because of the perspective that there is an individual and a group in one story, it is easy to mistake the issue as being between a society's decrees and the freedom of the individual, when really both are descended from the rights of one.
That said, not all regulations of speech are proportional. There's something called a "drive-by banning" on Reddit, where subreddits will use an automated moderator that reads through the subscription list of every new user to and automatically bans them if they are subbed to hate-themed subreddits. It is not necessary to accept all regulation of speech as being in the interest of tolerance, in the same way that it is not necessary to approve of all court outcomes in order to view the justice system as legitimate. While I believe that there are places where detection of fascist dog-whistles goes too far, or where enthusiastic rhetoric too aggressively categorizes all of their opponents as the most extreme among them, this is neither representative of tolerance, or of the ways in which intolerance is drummed out. The punishment should fit the crime, and it's not illiberal to criticize individual punishments (or rhetoric) as being excessive.
But usually the opposition to the tolerant society is the view that there is no legitimate way for a body of people to enforce a social norm. Those who argue that intolerance should and must be tolerated will say that it is wrong to withhold your business from a bigot, or your personal attention, or your social gathering, and that their viewpoints should be accepted and normal. In my view, this is an issue of allowing intolerance to gain a foothold in tolerant society, and the suppression of the anti-intolerant reaction is both a greater transgression against rights, and moves further towards the overthrow of tolerance as a concept. The argument goes that they never agreed to any rules of conduct, signed no social contract, and therefore discrimination against their ideas or expressions is wrong. Not realizing of course that the discrimination of the individual to choose how, and with whom they interact is as inalienable as freedom gets.
Out from the kitchen to the bedroom to the hallway
Your friend apologizes, he could see it my way
He let the contents of the bottle do the thinking
Can't shake the devil's hand and say "You're only kidding."
The remaining complication is this issue of violence. Can it be said that breaking the law to enforce a social norm can be right? Can it be said that violence in response to a non-violent act can be right? If fascism relies on violence to take power, is it too late to use violence once they've already started? Does using violence make it futile and undo the progress we've made? Is it civilized to make someone fear the repercussion of violence, whether or not it actually comes? These are tough questions, and I'm afraid that I don't have anything decisive about most of them. If it can be said to be effective, then there must be a very good reason why it should be categorically outlawed, or else it should be considered as a possibility. After all, if non-violent disagreement is supposed to be enough to stop modern fascists, then why was it powerless to affect either the rise or fall of Nazi Germany?
Then again, maybe the stakes just aren't that high. Hear them out, and let them actually be wrong before you shut them down. Who knows, maybe disapproval from a friend might sway them more than acceptance from a like-minded stranger. And in the parlance of the times: for God's sake, I just wanna grill.