It really just seems like you're looking at this with a very limited, black and white perspective. That's your prerogative but it doesn't really line up with the experience of most of the service members I've known and spoken with both personally and professionally.

I can't speak much to the experience of soldiers from other countries but people come into military service in the US from the full spectrum of the country. Wealthy families with generations of decorated officers to young people who really have no better option when it comes to their future. You may disagree with the entire idea of the armed forces but the reality is, especially for those who come from poor socio-economic backgrounds, there is no better option. A stable job that will provide housing, healthcare and education and a ticket away from whatever other negative things that may be going in their life. It's an alluring prospect. (Recruitment practices get pretty gross, I'm sure we can both agree there, but the benefits are very real).

Whether or not that is right is certainly something we can and should debate as a society, but there are a vast number of reasons people joined the armed forces and most of them aren't because they want to do bad things.