The skill is debate and debunking. It should be fairly simple to show a serial lack of honesty and bullshit. If you can show that then it should be fairly simple to get people to stop listening and disconnect. Calling their words mean will convince no one. Do the work if you care so much.
It’s not a debate skill issue, it’s an education issue. What bad faith actors do when pretending to debate is just real-time trolling, they’re not interested in debate, and debating lends legitimacy to their idiocy. “Don’t feed the troll.” People need to educated enough that they themselves walk away from disingenuous debates and stop listening.
Why would I claim the bigots would stop. I only claim that they would fail. They have the right to continue. They have the right to be wrong.