It seems to me like you tend to hear the most extreme and illogical views (on both ends of the political spectrum) from people who surround themselves with people of similar views (who therefore will echo whatever opinions they have in discussions), only listen to or read stuff they agree with, and think of people with different views as stereotypes, rather than actually listening to them. This is true of some (but not all) anti-war protestors and a few (but not all) people who stage pro-war counter-protests. Usually arguments between two people with opposite views but this same general characteristic in their way of thinking will degenerate into unproductive shouting matches.
The thing to remember in talking to anti-war protestors is that it's generally not helpful to be that type of person. It might feel really satisfying to yell something accusatory at someone with different views (that's often why anti-war people look for people who are in or are joining the military to shout at), but in the end it doesn't get you or the other person anywhere. So, when you talk to these people, just think about what you want to accomplish. You're not getting anywhere by getting into a shouting contest, so if it looks like that's going to happen, it's probably best to just take the high road, ignore them and walk away. On the other hand, if you actually want to possibly change their mind or get them to think more open-mindedly about the military (if they happen to be, say, your parents), you're going to have to have a lot of patience and maybe even listen to what they have to say, however ridiculous it may be or sound, since they're a lot more likely to listen to you if you do that. It also doesn't hurt if their opinions are based on a stereotype and you wind up completely blowing that stereotype away.
