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?