it's because (in the US at least) the "Skinhead" subculture has been colonized by neo-nazis to such an extent that they're basically synonymous. also falling back on pedantries like "I'm not a nazi because I'm not a member of the german national socialist party" is how nazis try to deflect people calling them out.
edit: just realized you said it was /r/bald... very strange that people on /r/bald would start calling someone a nazi for having a shaved head. i think you got called a nazi for something else, and the content of this comment makes me think they were right.
e2: account is 10 days old, refers to women as "females", and likes to whine about anti-white racism. tag appropriately
e3: a reddit account with the same username exists, but they've had a bot overwrite their comment history with gibberish. can't find shit from them posted to /r/bald, so it looks like that's just an out and out lie. why would you tell on yourself this hard?
No. Nobody likes registering accounts for random services because an authority figure told them they had to, I feel like if it were me I would do the bare minimum of interacting that I was required to and never look at the service again out of resentment.