once it’s moderated, there are already people reading it and the damage is already done, so the posters should be careful anyhow, so it wouldn’t make sense to say that someone wouldn’t be careful about what they write because they know they can edit after moderation!! At that point the damage has already been done!!
This would be true only if people were robots.
But people are not robots. They don’t through a whole specific thought process before posting. Rather they have a general mindset when posting. If there were no concept of editing a post, people would have a more cautious mindset when posting.
I think that ideally we shouldn’t be able to edit at all, but for whatever reason, typos often become more visible once you see the post in the thread (maybe it’s something about the formatting).