I'm not familiar with the Cam4 site, but Nazi paraphernalia is very, very popular in the European gay male BDSM scene. In particular a lot of BDSM bottoms want guys with semi-germanic accents to role play in nazi type gear. So, a guy from the Netherlands may have no nazi tendencies at all but may have realized that it will get him a lot of attention from bottoms if he's into topping.