Hildy, Pit Bulls are no more aggressive than their owners allow them to be. It is the same with any dog of any breed. The trouble is that pit bulls are breed to be physically imposing creatures, and when they are trained to be aggressive they do so with all of that physical ability behind them. You can train a chijuajua to be equally aggressive, yet they will be much less dangerous for obvious reasons.
Lurker, try to be nice won't you. I mean we are all adults here aren't we? If you're not, I appologize, continue being childish.
And you notice the behavior of the 11 year old who tried to punch the cop?