Maybe the "stigma" exists because different people value different things. Did you ever think of that? Or are you too busy assuming the people that are against toting guns and hurting people are just "scared"?
To join the military means that you are okay with killing people, because you are told to. Every human being has their own story and reasons for doing the things they do. That stands true for both sides of a war, not just one. It is easy and simple-minded to look at a war as "good guys" vs. "bad guys", but that is simply not true. There are many people that are fighting wars to protect their families or because they are forced to by their government. These in many cases are good people that would not hurt someone by choice. But when you're in the military, it is your job to defeat the enemy. There is no room to weed out the good people from the bad.
For those of us who understand the value of life and that all men have the right to live, we choose to not take up arms against other human beings.At least not unless forced to do so in an extreme situation.
That is not a fear-based decision. It is a personal decision based on morals. For some people it is a religious choice. Jesus would not kill another man, no matter what that man did to him, his family, his country, etc. He believed the only judge was God. Personally, this is not my religion, but it is a good example of why some people are so strongly against war.
For me, it is simply logic. I will not hurt, maim, or kill a stranger just because an authority figure orders me to. And I think it takes a certain kind of person to be willing to do that. I will never be one and I will never support the concept of being one. It is bad for the soul.