Antikayfabe is when you treat make-believe as real and hurt yourself because you’re not in on a salient half-ironic belief state. Like kids in capes hurting themselves jumping off roofs thinking they can fly like Superman. A lot of political action today seems antikayfabe now.
Most antikayfabe doesn’t have a single origin though, especially on the left, so the argument gets weaker as you get away from clear cases of incitement to generally contributing to a radicalized environment. Ie antikayfabe can happen even without kayfabe at the center.