Well expressed, but I would have approached it a bit differantly.
To be honest I don't think there are that many people who are just outright dicks. It comes down to differances in point of view, philsophy, and well.. existance. Two people can hate each other for perfectly valid and irresolvable reasons.
The problem with this system is that it works under the assumption that there is a litmus test to who the good people and the bad people are. In the end there isn't one, all that exists is of course Gabe's own opinion as to what's positive and negative, and his system then comes down to him saying "I want to run STEAM like my own personal empire, reward those I like, and torment those I don't", which makes him just another tyrant, there is no great plan involved here, just base egomania for him looking for a way of discarding any kind of neutrality and professionalism in the guise of a social experiment.
To take a big issue for example. Like it or not the population is pretty much divided 50-50 on issues like homosexuality, which actually consists of a number of related but seperate issues, but the point isn't the arguement itself, but merely that it exists. Let's say Gabe decides that anyone who is "Homophobic" by saying they don't like gays or whatever, is by definition going in the bad people bin. The term "Homophobic" in of itself a loaded term designed to trivialize the other side, by implying they are in some way flawed or in fear of what they don't like, and thus inherantly breeds conflict and tends to prevent serious discourse of the subject when used, leading to the issue continue to endure... and well it isn't about the arguement. The point is that Gabe is making a personal jugement on who is a dick if he was to do that. He's a tyrant, charging people extra money, to play games, because he doesn't like their politics, forget that he pretty much just set himself in opposition to what is honestly about 50% of the population right there. A guy who doesn't like gays might be a great guy, get along with just about everyone, and be a positive influance on the games, but he's in the dick column, because Gabe put him there.
The point being, that such a system cannot be used unless there is some fairly impartial way of administrating it, and human nature being what it is, there isn't one. It all comes down to establishing a cult of personality which winds up having nothing to do with the games themselves or what is good for the community.
It's sort of like how a guy from India and a guy from Pakistan could go at it for hours about their cultural conflict, who wronged who, who is right and who is wrong, those god or gods can beat whom up, and whatever else. They both think themselves to be right, and the other guy to be wrong.
Neutrality, or rather I should say professionalism, evolved in business specifically to avoid these kinds of issues. Especially seeing if Gabe DOES do something like this, he's probably going to cut his business down substantially as few people are going to pay extra for a product from him, when they can buy it froma competitor that maintains neutrality for less. He's also liable to get himself sued back to the stone age, since if he started charging people extra money to use programs they already own on STEAM, well I don't think that will end well for him.