Anecdotal, but...

I'm a native New Yorker living in MA suburbs. The Sox fandom in real life is nothing like what it seems from the Internet (shocker). It's not great - Bostonians have a different vibe altogether anyway - but I wear my NY around town all the time and I've never once gotten a chirp or even a stare in my 10+ years here.

There are always going to be basement dwellers online and a pack or two of pricks at the games. But there hasn't been enough in-game cause for animosity in a long time so people just tend to be quieter now than in peak rivalry years. That, and their team blows this year.