There is no place for racism, misogyny, and homophobia in our game. In severe cases, the floor should get involved. Otherwise, at a full table, the task of calling out bad behavior should rotate a bit so the labor doesn't fall on the same individual each time.
It's also a good idea to try and sniff out the dog whistles before it turns into truly hateful speech. When you hear a dog whistle, try asking, 'What do you mean?' or 'What point are you making?' as that often causes back-pedaling