Lol, why so cynical?
It’s true that you used to be able to like/unlike a blog after a while, but what if someone writes a really good blog, then gets hacked, the blog gets replaced with troll stuff, and people suddenly come in and look at it, and say, this is what the community likes?
Probably won’t ever happen, but I don’t see why there’s a limit on up/down voting either. :p