Your vision is great, of course, though I think you would find it to be a little unrealistic in practice. People take personal feedback (and especially criticism) very personally, and public shaming or labeling a user is harmful for everyone involved. These systems can help foster a more helpful and positive atmosphere in web forums by encouraging "better" users to post more, but does little to encourage the "worse" users to improve.
The social dynamics you've described are the result of a growing site that attracts a larger audience, both good and bad - concerns similar to yours have been voiced since the site first began to grow beyond the original tightly-knit group of friends. In addition, the surprisingly complex and wide-ranging reactions and opinions about Gran Turismo 5 stretch far beyond the scope of this community, and make emotions run at unreasonably high levels.
A good way to address a user who you feel is bad for the site is, of course, to report them to our moderation staff or bring them to our attention in some way. The most important thing you can do, however, is summed up by two quotes: "Be the change you want to see in the world" and "Evil will prevail when good men do nothing." If you see someone being "bad" to someone else, report them and reply to the other user's post in a positive way by answering their question or just acknowledging what they said. You'll feel good for helping someone out and by keeping things positive, you'll indirectly keep the community going in the direction you want it to.
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