Are We More Violent?

I have been noticing that many times when a person commits a terrible act, we automatically assume they are mentally ill or the press tells us they are. I for one find this annoying and many times downright angering. As a person with a mental illness, I find it degrading that someone would think I'm more capable of violence simply because I have an illness. That's like saying, left-handed people are Communists! Almost any person with an illness is no more likely to commit violence than any other regular person.
It angers me because it seems that mental illness is being used as a crutch to get the person out of lifetime or death sentences. I have bipolar, guess what I have never thought nor am I more inclined to commit mass murder. I've been severely depressed even suicidal and I've never tried to fly a plane into a mountain! Even at the height of my illness, I know the difference between right and wrong, I may be harmful to myself (not that that is ok) but rarely have I done anything more than raise my voice to others. Even if a person has a mental illness it does not play the final role in their actions, they deserve to be tried and convicted based on all their actions not just an illness. The very few mentally ill individuals who are truly a danger to society and themselves usually don't have the capacity to plan, prepare, and execute mass violence; their brain simply cannot work that way and many times they are hospitalized due to being unable to function in society. And if a person can think this way and prepare, plan, and execute such an operation, then that's fine proof that they are clearly thinking quite rationally in terms of right and wrong.
When people are told that the mentally ill commit more violence it just feeds the myth that they are scary and violent. When people believe this, then the mentally ill are more isolated and in some circumstances even harmed because others believe they may be hurt. This is many times even more noticeable if the person is a veteran with a mental illness. What is it about being a veteran that makes us more scary to people? Why do so many think that we will "snap" and begin killing everyone? This doesn't even really hold true with most mass killers, yes some are prior service but by far most aren't. So why are we even scarier?
Some may say it is because we have been violent or seen violence. That because of our training we are more quick to use violence as a weapon. I say that it's because of these reasons that most veterans are actually less likely to resort to violence. When a person has seen the damage violence can do, when they get the brutal final lesson of combat which is the ending of another's life, then they are much less likely to ever want to repeat it. If people think that veterans are possibly so "violent" then why are so many of us having problems returning home? Why do we have the nightmares, flashbacks, paranoia, anxiety, and depression? Because we are trained violent monsters who love to harm and kill? No, it's because we did things that for some of us went against the way our minds operated and now our violence has become our nightmare.
Most of us, both veterans and those with illnesses, just want to belong to a society where we don't have to hide. I'm grateful that I have a group of friends who I can tell them when I'm having a difficult day. When things are making sense in my head, they simply allow me the space or try and help me figure it out. I don't have to feel like there is a part of me that I have to conceal from them. But there are many people who don't have a support system or are too afraid of rejection to tell others.