As a counter point: most young men I knew growing up (in a upper middle class, left leaning neighborhood) really could have used some time in the military. I know I could have. I ended up getting a similar-ish experience working construction.

And that's just at the personal development level. As a society, I think some kind of compulsory service (not necessarily military, but military as an option) for young men and women would go a long way toward healing the political, class, and racial divisions in the US. It's hard to other a group of people when you've worked alongside and bonded with individuals of that group.