They don't need to admit anything. Groyers as they are can just as easily cohabit a house or a suburb under their current belief structure. There are more than enough of them. They don't need to fall in with anyone until local defense morphs into regional defense.I'm not involved into the whole "community" thing, mostly because I already have a place I can go but also because I am in a position where I don't have time. But from what I can gather, the Alt-Right already has real world communities and get together's and their own networking.
What you are suggesting already exists in the USA, because for at least this time, it is still legal to do so. How much longer will that be true I can't say.
And my point is Fuentes and the Groypers need to admit to themselves and their followers that they were wrong and the Alt-Right that they attacked for no legit reason is the truth and to join in. After that they can become part of their real world community.