“Song From MASH (Suicide Is Painless)”
[…]It goes without saying that suicide isn’t painless. Even if you are lucky enough to do it in a manner which doesn’t hurt yourself and it can go wrong so easily, the people left behind are left with a lot a pain to deal with so… thanks lyrics.
I think the point is that suicide would be painless in comparison to the pain of the war. The song was also written to be comical (in context), and it does it’s job well; it just happens to be a little deeper underneath the scene.