I'm not certain about elsewhere, but here in the US I place a good portion of the blame on mass media. Far too often I see combat PTSD veterans shown in only two ways: the gun toting meat eating John Rambo type that suffers a psychotic break and shoots up a restaurant, or takes his family hostage and holes up in the house; and the ultra depressed, moody melodramatic whiner with what the public calls an overblown sense of entitlement.
Now, take what the folks see on the News at night and throw in the EXACT SAME portrayals by the entertainment media, and you end up with Americans that know everything, or think they do. Even more insulting, they drive around with those stupid, overpriced, Chinese made yellow ribbon magnets on their cars, or wear "I support our Troops" t-shirts and have never actually done ANYTHING to support the troops.
I feel that as long as we continue to allow civilians to picture us as some hollywood drama stereotype or mass murdering monsters the pervasive ignorance will only get worse.
I, and Po-dog, used to volunteer quite a bit with other PTSD vets, but we don't anymore. I find that while you know where I lay blame, I haven't mentioned that we the vets are just as much at fault. We have allowed civilians to portray us incorrectly to other civilians. My personal experience thus far is that many PTSD vets reject help, interaction, or treatment. They are so caught up in the pre-programmed us vs. them mentality that they are not willing to put forth the effort to even try.
I guess what I am trying to get at is that the only way to deal with ignorant, impressionable civilians is to learn ourselves how to not be typified and take steps as a whole to get the right information out there and hope. We cannot coerce the ignorant to change, but we can provide them with the information they need to do so.