Replies affect, because it is quite rare situation where a topic means one starter and plenty of separate replies to the starter
After anonymatization? How’s that possible?
Yes, that it means. And that policy is quite world wide and where things are differently it comes from goverment-level and has nothing to do with a user; what China does is different thing than what GDPR of EU states.
Yes, it means that (quite universal thing and has nothing to do with Discourse).
There could be one rare situation when such policy is actually unlegal, in western countries anyway. If a post is so original that copyright kics in — copyright is better protected than agreements between platform and users, but it can lead to very expensive trials because just opinion of a user when a post is original enough is not enough.
In the real world admins mostly will do such deletion when asked — if they can do it technically (I can’t at my forum) or request doesn’t break too much topics.
Still… there is one bigger question too: can a single person change ones mind when wanted and is that stronger thing than benefits of many as a community. But that is more or less at philosophic level, I know.
(Sorry, I’m reaching the limits of my english skills, so please try to see behind all grammatic errors and different way to style sayings what a native anglo would do…)
And the last disclaimer: I don’t know what admins here, there and everywhere do and don’t do; out there is different laws and rules too, but things are quite universal world wide too.