It is harder to be a troll when anonymity is removed. People, at least some people, will be more hesitant to post stupid things if their stupidity is associated with their real world identity for all to see. It would also be more challenging to be a criminal or fraudster online when anonymity is voided.

Just think how much less toxic Reddit would be if there were no anonymity and employers, parents, and neighbors could see what people are really thinking about.

Also, privacy is not anonymity.