In my experience flagged comments are typically off topic or abusive. I don't recall ever seeing a flagged comment that was an honest attempt at discussion. As for grayed comments that are an honest attempt at discussion? Very common. I upvote heavily downvoted comments that didn't deserve it almost daily here. I've also been the victim of massive downvoting merely because I present a viewpoint that the hive-mind doesn't like. If you're only interested in a single viewpoint and don't want to see all sides to a topic, then sure, this system is great. I like seeing more viewpoints and perspectives.