@siderea@isagalaev@jwz I agree with you that YouTube comments where you can up/downvote don't really translate to Mastodon and would like to see the feature described implemented. It's having one side be in complete control of a discussion by default that I'm concerned about.
Not every poster wants a discussion at all of course and if a thread is started with this option on, it should be indicated in the initial post that replies are at the discretion of the poster. An option to only allow people you follow to reply would also be a great option to have. If you want an open discussion you'd have third party moderators and turn this off.
For content on YouTube, reading comments and checking up/downvote ratio (was) used that to get an initial take on video accuracy. Less so now since they removed it and the author can delete any comments that are in disagreement. Many users still install third party extensions to recover that functionality to some degree like: https://returnyoutubedislike.com