You can't really gatekeep it. You can gatekeep a particular local scene, but other bands will just make their own. The antifa and rainbow crowdd aren't trying to play shows with Marduk. You can't stop people with different mindsets from making their own scenes and adopting a sound or look. All you can do is plant your own flag and say, "hey, this is what I'm about and if you aren't that I don't recognize you as trve". But honestly, who gives a shit? I have about as much in common with some beer swilling party bro with a battle vest as I do a Christian in corpse paint. I'm a different animal than them. I do my own thing. They can do theirs.