No matter the ideology, you will run into purists who try to say who can wear the label and who can't. I've personally run across that with upper case Libertarians, those who belong to the party and claim to be purists. I've been told I'm not libertarian because I believe differently on a few issues.
It seems, daily, I find anarchists who sometimes carry the Libertarian label. On a given day I'll find an anarchist who claims to be a progressive. I watch as people who all carry the same label, arguing over some issue.