I’ve adopted a similar tactic for dealing with racist and homophobic jokes. Instead of getting indignant and launching accusations, I play dumb. Pretend like I don’t get the joke. And then I get them to walk me through it. Explain why it’s supposed to be funny.

When it’s a joke, they can hide behind it. “It’s just a joke! Where’s your sense of humor?”

But that doesn’t really fly when they’re trying to deconstruct the joke and explain to you why it’s funny. That reveals the racism/homophobia in a way they can’t hide from.