As humanity as a construct is difficult to define, I'll propose a metaphor which fully describes the multi-faceted and truly horrible thing which is mankind:

Alright, in order to picture humanity, imagine that someone had a vat. A vat filled with monkeys. Monkeys which had been shaven. Now, into this vat of monkeys, we add: knives, guns, bombs, rampant monkey porn, Valium, Thorazine, Prozac, heroine, cocaine, missles, designer monkey clothes that only a few monkeys can afford, brass knuckles, clubs, and, finally, slightly deficient supplies of food, water, and suitable monkey mates for each monkey.

Now, as we cannot put 6 billion shaven monkeys in a vat without being sued, bombed, or justifiably assaulted, we must mimic the effect. So, we take our vat, and put it into a car crusher. Now, we slowly apply pressure to the vat, until all these monkeys, with all of their monkey weapons, monkey porn, monkey reliious ideas, and homicidal monkey tendancies are shoulder to shoulder.

That's humanity.