It seems like most people who support that kind of censorship are indeed short-sighted of how it can be used against them in the future, but there are also bad actors that just want to destabilize everything because it fits in with their goal making conditions bad enough that it will be easier to "smash the X" (patriarchy, capitalism, social classes, etc). Anything that upsets what they perceive as the "established order" is good, because it gives a better foothold to advance their other agendas.