People keep confusing extreme disapproval of ideas with censorship. If you say "the Holocaust didn't happen!" and people decide that they don't want to be your friend anymore and private organizations like corporations and universities decide to no-platform you, that's not censorship. That's just people exercising their free choice en masse.

There are some ideas that are justifiably extremely unpopular: racism, extreme religious bigotry, advocacy of genocide or apology for such, etc.