It is a pretty big difference when the left wing cancel culture is a grassroots efforts of the populace trying to enforce moral behavior versus the right wing cancel culture we are seeing today in which the government is the one exerting pressure and not the populace.
Oh, sweet summer child. It's as "grassroots" as the Cultural Revolution (party elites encouraging and directing mobilized workers and farmers to play out their power plays) was grassroot.
The FBI and others telling Twitter what to censor, the goverment agencies threating companies to comply, academics and prestigious news media on lockstep, nebulous NGOs and "think tanks" suggesting what's fake news and what's not, tech behemoths collaborating, even banks having a go at it.
In other words, it's as top down as the current Republican shit is.