How would you know? You’d have to scan the thread looking for red pencils.
I’m thinking the most likely person affected is another party to the conversation, who (after the edit) is made to look stupid, to anyone coming along later and reading the conversation. And the person who makes the edit might look less stupid, because they corrected or removed something.
It’s in a heated argument that you least want people to be rewriting history. That kind of deception undermines community.