A few notes. Yes, the SS tats and symbols are def a thing in the Marines, never saw them myself on anyone though. I can vouch for being young and dumb as a possibility for making stupid decisions and not knowing a lot of those symbols, and fascism is def baked into the cake in the US military. But decades later, no shot.
Also, Croatian tattoo artists probably don't offer non-Nazi skull and cross bones too often. But their history of being aligned with the Axis isn't well known by the public.
At any rate, I can break down his explanation of the culture that he doesn't get because he's too stupid.
Groups of young men become psychologically damaged by doing horrific things that they're lead to believe are good. Their own nature struggles to reconcile doing wrong while thinking they're doing right. This creates an emotionally volatile state that could be described as neuroses. Many turn to drinking, heavily, further dulling their mental faculties. They do so together and trauma bond while never actually discussing the energy it takes to not recognize the cognitive dissonance. They encourage each other in all of these behaviors and reinforce them amongst each other, leading to further mental and emotional instability, and further efforts to supress it. Feeling like they belong to something exclusive that backs up their sense of being a self-sacrificing hero easily draws them in due to their emotionally vulnerable state, so they'll go along with whatever symbolic tradition that makes them feel like they're in the club. Repeat ad nauseum.
In short, they're a high school clique that murders people and everyone in it becomes an alcoholic because they're mentally stunted by their occupation.
It's that fucking simple, there's no mystery. This is just hand waiving away reality and the idea that there's anything wrong about what they do.
Having worked in schools at one point and knowing a lot of teachers who I have a world of respect for, yeah. And most of the smart teachers know this too and are trying to help younger people to see. But at the same time they still have to teach them how to survive in a system that's not going to change over night.
Fuk.... I use Fedora on pretty much all my machines.