I think the inward-lookingness of cancellation is key here. Regarding attempts at totality, in the past, if you were cancelled, it was because you were group A masquerading in a group B world, and group B found out and kicked you out of B-world. But, importantly, Group B couldn't cancel you in the eyes of Group A, only in their own eyes. So if you were found out, your direct life got cancelled but there was frequently another segment of society welcoming you with open arms.
But now with the inward-lookingness of cancellation, you have people from group B who are cancelled by group B, and have no one to fall back on.
An example would be a teacher arguing for the support of gay marriage getting cancelled by a catholic school they work for. That person, in the past, could pick up their bags and move in with the liberals next door. Yes, they lost their job, and maybe half of their associates, but they still have the other half who would be more than welcoming of them for the plight they've been through.
But what happens when a group cancels their own? For example, the Peru N-word journo. By all appearances, he is a liberal-minded person, who worked for a liberal-minded newspaper, in one of the most liberal-minded cities in the nation. But now he got cancelled by his colleagues. What is he supposed to do - go hang out with white supremacists? Neither side would find that appealing. So instead he has to...not partake in society at all?