One that discriminates against other rock sub-genres. This person doesn't appreciate the widely diverce world of rock n roll and would rather stick to that one lonely sub-genre. This person could like 80s hair metal and resent grunge or like punk and hate arena/hard rock etc etc. Or maybe they could just like metal and hate everything else. Rock nazis really need to stop being such snobs and open their eyes. Whether it's blues rock, alt rock, punk or whatever (except for pop rock and emo. Most people agree that's not even real rock n roll anyway.) As I was saying, just try listening to something a little out of your comfort zone. Try it. You might like it.
"Look at the guy in the Dyeing Fetus t-shirt putting down The Doors. Damn rock nazi.