And it's not even specific to the military. Everyone does it.[/LIST]
When you're in a unit, any unit, you feel like you can trust your own and you usually view people in other units with a skeptical eye. reservists really get a lot of this from the active duty folks...
Try mingling around the UC Berkeley campus in uniform. Not everyone's going to greet you with open arms and, often, it's not unusual to get verbally harassed or ostracized. The sad fact is that college campuses which purportedly advocate freedom of thought are the nidus of social elitism. I should know, I was a graduate of UCB. (I'm not saying we're all like that but many folks are vocal about their disdain for the military.)