>and there are already so many people grandstanding to each other all the time that it's just more noise on the noise pile.

This is true to an extent. If you're in a 500 comment thread, and the point you want to make has already been made by a few other people, there's little point in dogpiling in yourself. However, this isn't always true. If you're adding new information/perspectives, I don't see how that's "just more noise on the noise pile".