Sure, some short guys tend to be more twitchy and defensive, but is it solely due to our height? No, because while being short wouldn't make us more aggressive, the treatment we might have received for being short have made us aggressive.
This goes for all groups subject to discrimination. If no prejudice came our way, I guarantee we couldn't care less about whatever it is we're mad about. Why would any man hate being short if nobody made it seem like a bad thing?
When you are perceived as inherently inferior, and any attempt to improve yourself means you're compensating, you're trapped and caged animals lash out. When you're randomly watching a movie and a short guy is the one idiot in a group of tall men, that's kinda fishy. When you meet someone and the first thing they say is "ha, you're short," that's fucking bullshit. With this constant annoyance, is it so shocking that certain short guys lose their minds?
Point is, if you see a bitter short guy, it doesn't mean he's bitter because he's short. Personally, I'm mad because society is full of shallow assholes.