Alerts can be turned off for registered users so they're not informed of them.
I like being agreed with, it's a good feeling. I like seeing disagree as well so i can address it. I don't like seeing dislike but it makes me think about the post and I probably deserved the dislike. Overall, no big issue.
Giving option not see your own ratings is a great idea. I will implement only if a registered user asks for it.