I think the best answer to these divisive, sexist or racist behaviors is to show them in practice they're dumb, kick their ass in the market.
An open-minded, welcoming organization is going to attract the best minds. Collectively, these people will kick those ideological-driven asses.
EDIT: my point is we cannot legislate change to these people's minds. The only sustainable way forward is to let reality teach them. If we try to impose change like this, it'll only lead to more divisions in society.
If I see a lot of racist behaviors against blacks, or latinos or whatever, I'd be glad to join them and work hard to kick these racists out of the game.