Am i being childish or is my neighbor just really annoying and inconsiderate?

Don't respect veterans for surviving, respect them for suffering on our part. Even if this guy is a veteran it doesn't give him the right to nearly kill people then swear at them about it, but to be honest, experiencing a concentration camp is sure to damage your mental health some how, just be considerate of that. If he acts dangerously in the future or if you think he is threatening others safety, don't hesitate to take legal action.