Not a lawyer but I don’t think that matters. Twitter isn’t using the mark for a service about video games, inasmuch as nobody would describe Twitter in one sent

Not a lawyer but I don’t think that matters. Twitter isn’t using the mark for a service about video games, inasmuch as nobody would describe Twitter in one sentence as “a messaging platform about video games” any more than they’d describe email or SMS that way. You never know but I think this would be too far of a stretch to pose a real risk.