It's for feedback. It's also for community discussion. Someone could leave feedback and the rest of the community has a chance to discuss their own take on the subject.
The Community team probably scans on a regular basis for new topics that may actually include feedback/suggestions on topics that the development team hasn't already addressed in some way. Some may end up missed in the general chaos but we know some do make it to the developers because we've seen responses.
The problem is the players who demand that their thread become an echo chamber supporting their idea and that those who disagree shouldn't post. That's not the way it works. If you can't handle disagreement with your ideas, then don't post them in the official forums. Post them through the Suggestion portion of the Support Desk instead.