If you assume that all opposing opinions come from flat-earthers and idiots that couldn't possibly be right about anything you will never even think about changing your opinion on anything. You'll continue to chat with other reddit yes-men and pat yourselves on the back about how you're all so right.
The upvote / downvote self-censorship system simply does not work for any serious discussions. It might be ok for sorting the snarkiest comment under an article but that's about it