But who's handwaving the problem away? My point wasn't and has never been "someone else can deal with that", it's just focusing on the club affiliation of these people is often reductive to the overall meaning of the discussion.

Let me put something else to you: say someone racially abuses Anthony Mackie but they're a massive Marvel film fan, does that mean we cannot denounce the racism without mentioning their affiliation for Marvel?

We need to snap out of this very devaluing mindset of attaching extraneous information to these things. Again, it doesn't matter whether someone is a Liverpool, United or Everton fan - if they're a racist then they're a racist, and we should approach the situation as such.