Blacklisting in the sense referred to here is not censoring. It's a way a user can put a warning beside an account's name, to remind themselves (and potentially others, if they opt-in to use your blacklist) that interactions with that account should be handled with care.

Truthfully, blacklisting is probably the wrong word to describe what this feature does, but it's the existing name that's been used for the centralized version of this feature, so I continued to use it for continuity purposes.