Because obviously, one person with a certain ideological bent speaks for every person with that same ideology.
By the way, you should have spoken up if you knew unequivocally that the black thug was the attacker, especially when there was absolutely no evidence of that whatsoever, besides the testimony of accused. You could have really helped your guy's case.
PS. As for your suggestion for me to speak up - luckily prosecution brought a witness who testified that TM had been attacking GZ, so no need for me to do the same.
This square peg of a criminal case was jammed into the round hole of a political issue when Obama made his statement about if Trayvon was his son. Since there are millions of people in this country whose stances on various issues consist singularly of the opposing view of whatever Obama's view on the issue is, George Zimmerman became a conservative hero.
So to paint overreaction and the abandonment of logic and reason as a tenet of liberalism is downright ludicrous.
The whole distinction between one element of a set and a whole set seems to be incomprehensible to modern liberals. E.g. the recent example of shooting an attacking black thug had been made an example of racism. Because, obviously, somebody who shoots a black person to protect his life is principally against the entire black race.