Is my boss really allowed to discuss the 'double standards' of racism?

I think he's a white supremacist. He just fired a friend of mine for making Irish jokes. He wanted to know why it's ok to make jokes about the Irish, British, Germanic etc but it's practically forbidden to make fun of Jews or blacks. He's white and he hates 'anti white' (his words) attitudes. Is he crazy or just a nazi wannabe?