I fail to see why people would make a conscious effort to be anything besides themselves, especially considering that the others factors would not count towards ranking up.
Because it's there. That is human nature.
However, I do get the fact that a sense of humor has never been a strong factor at this forum nor to be polite when dealing with others. I've had many posts deleted as a result of it. It is much better to be cold hearted and dead serious. I also get the notion entertained by many that intelligence and a sense of humor are not good bed mates.
I would disagree with this and theymos's joke is a great example to prove the point. The only things you can do to get a better score is spam, but then that doesn't actually get you anywhere because it's random. A brilliant joke.