>Some people are able to honestly assess their past positions and statements, understand why things could be construed as problematic, and make efforts to better themselves. That, and a sense of what conversations are appropriate for public forums versus informal conversation over drinks, act as pretty great cancellation buffers.

This is wonderfully sensible when the problematic things in question are unequivocally problematic (e.g. justification of genocide, or explicit racism). For those things that are borderline, as well as those whose problematic nature is in dispute, it's not so clear cut. Herein lies a strategy for silencing a viewpoint - descend on those who express it with vigorous Twitter fury, deprive a few of them of their livelihoods, et voila! Something that has been discussed in public (and perhaps ought to be discussed) is now confined to "informal conversation over drinks". The offensive-to-some viewpoint is silenced, all is well!

Well, not to me. I am a liberal, and thus I believe that discussion and disagreement over ideas helps improve the good ones and helps sink the bad ones. Disagreement is not a chore, it's the fundamental feature that every free society should cherish. But we should probably restrict justification of genocide, and explicit racism.