I'm only guessing, but I assume email is likely to help cut down on spam bots. Maybe? (Someone do tell me if that's wrong. I wouldn't mind learning something!)
I know some users here say seeing who upvotes promotes transparency. Maybe you're less likely to upvote some hatespeech if you're attached to it and not doing so anonymously. Which then means it gets less traction and the user feels less welcome. Which curbs it.
But then privacy is important, too. There's nothing wrong with me going to the adult store and buying a gimp suit for myself with the Anal Blaster Master 3000: Destroyer of Rims vibrating dildo pack. But I also don't need my neighbors or family to know. Just like I don't need people to know I upvoted that really hot video of a man smearing chunky peanut butter on his incredibly hairy chest as a girl tries to lick it off.
I'm sticking around for now and seeing if things either change (like if the users for upvoted etc get hashed or something for example) and how things end up feeling in the long run with or without those changes.