In my experience with regular everyday xenophobes, if you simply say that the only thing that is important to you is that somebody is a good person and all else doesn't matter, almost everyone will agree.

Fighting is usually counter-prodactive, most people aren't crazy, they just might be focused on unimportant things. Simply calm people down and bring focus on important issues, such as worker rights, corruption, self-organizing. Don't waste your time debating who should be allowed to participate in which sport competition.