Would *love* to know the name of mr. 82nd airborne division here rendering hitler's nazi salute....

You'd be amazed at the number of people that join just so they can learn military tactics and weapons and take it back to their life-long goals of whatever. In the 80's and early 90's when the gangs were a huge problem the CMC sent out a White Letter about screening applicants, recruits, and active duty for tattoos and other characteristics that portrayed gang affiliation. Things like the teardrop near the eye and other gang markings flagged people for interviews. There are also people that just want the rush of killing somebody and are willing to go through the process to achieve it. Either way, they bring their training home with them and put it to use with an organization or as a lone wolf. Not everybody joins out of patriotism, and even some that do, become radicalized by others after joining.

Nothing new here. I would also lay a bet that there are a number of extremist in all branches and units of the Armed Forces of the United State, not just neo-Nazis, but MS-13 could be there as well.
This is not an excuse for any of these people, they are just as despicable as anyone else of an extreme nature. And we do grow our own nutcases as well (William Kreutzer, Jr.).
http://www.cnn.com/US/9602/ft_bragg/index.html
https://www.splcenter.org/fighting-hate/intelligence-report/2006/several-high-profile-racist-extremists-serve-us-military

And Mr. Nagel, I am positive that if we go back through both the military and news media reports, from today and going back to say the 1960's that we will find this in every branch of the service.

It could be and I hope that I am correct a guy that bought a hat at the flea market.