You will note that out ratings at wordpress.com do not preclude the option of negative votes. I could be wrong but I think that could be because it’s assumed all bloggers can learn just as much from truth telling readers as they can from fan boys and fan girls.
I know what you mean by a single hater. I’ve had a drunken druggie troll hassle me for two years now. I moderate all blog comments so I simply collect his and feed them to spam filters. Anyway I will flag this thread and ask our Moderators to move it to the Ideas Forum for you.