Show usernames on votes, and the topic of laughs as trolling

I’m fine with concept of downvoting, to balance out upvotes. But laughs are clearly used by some as a form of “trolling” or “shaming”, especially for adult-rated content. It promotes an antagonistic environment. Why allow a type of post, and then also allow mean-spirited troll votes?
More generally, why not just provide a way to show usernames, e.g. on hover? Or in the info pane?