That's an... idealist point of view. Would you consider yourself an optimist?
Honest question. Not trying to argue.
No, I consider myself a statistician. Now, maybe more people will, on average, smite than cheer. In which case all fu will go down. Or maybe the opposite. However, over time, simple averaging will cause people who have better or more useful ideas to go up more (or go down less) than people who harm the forum through their actions, as the more responsible people will be raising and lowering fu from a third party perspective in a reasonable way, and the trollish/smiter types are as likely to hit one person as another most of the time.
I mean, sure, there's going to be jerks who just lower the fu of anyone who they disapprove of or whatever. It happens. But it's just as likely that some people will be fanboys for someone else and raise them up, and while at the time that means the fu ratings are off, when it happens again with a different person it should start to average out. The more visible you are on the boards, the more your fu may vary when you do something, but if you're honestly contributing useful information or just being helpful it will go up and if you're honestly behaving in inappropriate ways, it'll go down.
It's like coin flipping. I can't say that you're going to flip heads or tails, but I can say that in 10,000 flips, you're going to get somewhere around 5000 heads.
JaronK