That also means that some users will be pressured to censor illegal speech no? If you live under e.g. a regime that disallows or discourages criticism, now suddenly the onus is on you to do something about those comments because you have the ability to. If you couldn't edit the comments it's not your fault.

Either way I think it's a pretty stupid feature the way it's implemented; it should show the edit more clearly or indicate that the comment has been written by multiple people (like StackOverflow does), especially if edits change more than e.g. 10% of the original comment.