Just so you guys know, nazi imagery in Eastern Europe usually has a lot more to do with anti-communism and anti-authoritarianism (ironic, I know). I'm not sure if Poland is westernised enough for nazi imagery to mean 'fuck the jews' instead of 'fuck the government', but in most ex-communist states it's largely the latter, and only slowly coming to incorporate the former. Keep in mind that Poland was under a communist regime for a pretty long time, and that the actual memory of that regime is far more real to the people there than the history of the Nazi occupation. And that's even if you discount the possibility he's wearing it just to be edgy (like Sid Vicious in his swastika shirt, for example)
I'm not saying these guys aren't neo-nazis, but to assume they are based on one guy wearing a shirt is pretty dumb, especially considering the cultural differences at play. These guys lived under a murderous communist regime and one of them is wearing an anti-communist militia shirt. It's a pretty big stretch to call them neo-nazis.