The US military, and probably all militaries ever, have a really quite low tolerance for fuckups. When somebody isn't dependable, when somebody doesn't exercise adequate restraint in their conduct, they get marginalized so they can't do too much damage, or simply gotten rid of.
All these youngsters join up, and have it drummed into them that they have these huge responsibilities to their fellow warriors and their nation, and they must do their jobs right. It's not just that they have to cover their squad mates in fire-fights, but things like, "If you don't clean this surface correctly, the guy who is going to try to land a plane on this deck will die and maybe take a bunch of us with it." And they discover, yes, they have it in them to do their jobs that well, that dependably. They are somebody who pulls his weight and can be counted on.
And furthermore, they discover they are in a whole society of people who are equally determined to be dependable, to pull their weight and be somebody who can be counted on. That can be a down-right rapturous experience; I know, because there's other ways to have at least some of that experience, such as through the performing arts, and having tasted it, I can attest it's positively intoxicating. It's like falling in love. Or maybe it is falling in love: this probably is more the basis of that intense camaraderie shared by veterans who served together than common adversity or common purpose.
Civilian society, as a whole, is, in contrast, replete with fuckups. People who can't get out of their own way enough to be depended on, people who don't take commitments seriously, people who are exploitative, who phone it in, to try to get away with minimal contributions, who don't care about those who rely on their work, who don't want to be relied upon, people who don't want to have self-restraint. We don't get to throw those people out of society, so there they are, being part of civilian society, fucking up, and their fucking up being tolerated.
People in the military, who subscribe to the discipline of speech and courtesy described above, are way, way, way, way, way too polite to actually come out and say, "We're different from civilians because we're not used to putting up with fuckups," but that is what it sounds like is lurking between the lines. It feels like they're trying to apologetically and politely say something that more bluntly put might sound like, "See, among us, fucking up is not okay; being a fuck up is not okay. We have these values and stuff which say it's not okay. And we totally get that that's okay in civilian life, where if you want to be a fuckup, that's your free choice. In our culture, the military culture, we see that as not a legitimate choice. We see that as bad – and comport ourselves accordingly."