I think the core of a lot of these issues is the distinction between universal findings which almost always are in favour of "progressive" worldviews and anecdotes which aren't necessarily. The example of trans people detransitioning is a good one here - the general truth that transgender people are very happy with their decision to do so (regardless of what that may mean for them) conflicts with individuals and their anecdotes regarding their (or people they know's) transition.

Whilst there isn't inherently incorrect or morally wrong about detransitioning in itself, often when brought up it can lead a person to an idea which is incorrect - essentially applying the anecdotal evidence of a Reddit thread to all situations.

Thus, moderators of subreddits (and administrators, although I think that whilst it is bad when they do so, it isn't as common as many would believe) feel conflicted on the matter. Should they allow the discussion to continue, almost guaranteeing that somebody is going to form misconceptions from the thread? Or should they shut it down, stifling free speech but at the same time reducing the level of overall animosity towards minorities in the community, and preventing people from forming misconceptions?

Ultimately, I think that it should always really come down on the side of free speech, as long as they aren't being blatantly hostile. However, in my opinion, if we really want to have a positive "marketplace of ideas", as some describe it, we really need to educate people from a young age on logical reasoning, cognitive biases and argumentative fallacies the same way we would teach history, geography or the arts. Whilst I think that's unlikely to happen in our current political climate, given that keeping people uneducated is a very effective way to make them vote for those who make the most compelling surface-level arguments, it seems to be the only good solution for the conflict laid out above.