By baiting, I mean posting deliberate dog whistles, often as crude proxies of what they fear and hate, and set off what is sometimes hours of chud barking in that area, whether it's a game's lobby chat or Discord or whatever.
Examples I've seen include old and exhausting shit like "did you just assume my gender" and "check your privilege, shitlord" 4chan greentext-tier staleness, but sometimes they can get slightly more cunning and insidious, such as portraying themselves as farcical LGBTQIA+ people then announcing an intent to do (conspiracies/crimes that chuds accuse LGBTQIA+ people of here) and keep up the whistling until every chud is barking across the site.
I do play some online games and calling out bait sometimes works, but it's still exhausting when a cooperative game shuts down because some chud starts a hate rally and effectively shuts down the game's cohesion for a while. 
I like to go all-in and ruin it for them.
It's only funny as a dogwhistle when they get the pavlovian response from their shitheel audience.
If you pretend that the joke is really funny and clever but especially original, and you ask where they came up with the idea for that joke it kills it for them because they are forced to confront the fact that they're rehashing a punchline without a joke that has been circulating for over a decade by this point.
They can't call you on it and say "Are you stupid? This joke is so old that you must have been in a coma if this is your first time hearing it." because then they're admitting that the best humour they can muster is a joke that is so tired that it's not even a joke anymore. [Insert Nietzsche quote about truth here]
Leaning into it kills the joke because it reveals the uncomfortable reality behind the joke that they don't want to acknowledge.
For extra points, if you are stuck in a small space with people like this, repeat the same joke over and over to run it into the ground and absolutely spoil it for them permanently, like a dad intentionally misusing terms like rizz so their kids will find it cringey and they'll immediately abandon using those words from that point on.
Holy shit this is based. If people generally don't like leftists, we can take whatever they do and make it "uncool".