Just glancing at the linked spreadsheet, I see way more than 4 events in 2020 for which termination is pretty clearly justified and necessary, so this trend seems to be driven at least in part by a change in behavior by professors and not just others' responses to that behavior. Also worth mentioning that the majority of the listed professors don't seem to have actually been fired or even disciplined - unsuccessful petitions and the like are included.

seeing a lot of people in this list "denounced in an open letter", "petitioned for firing" and the like. maybe we have different ideas about what it means to be "cancelled".