Just say: "Yeah, okay, we get it. You don't like 40K. Is there a point to this rant? Because we just want to play a game and won't force you to participate."
The tabletop gaming scene is full of passive-aggressive neckbeards who have no ability to be alpha males in the rest of life, so they inhabit that sphere where they think they do have it. Don't let them get to you.
oh thanks for the laugh in what society does this even work? this is on par with just ignore the bully he will get bored and go away...please imean no disrespect but that will never work..well unless your the hulk then maybe..
Most people have no capacity for confrontation. Honestly, you'd be surprised what a public shaming will do to shut most people up.
But if what I suggested above doesn't work, I agree that speaking to the manager about it is probably a good idea.