There's been a lot of controversy lately regarding YouTube and predatory content being added to both videos and in the comments of videos focused at kids. In response to this, YouTube's announced that it's now automatically banning comments from videos featuring children/minors.
Per a blog post published on February 28:
Over the past week, we disabled comments from tens of millions of videos that could be subject to predatory behavior. These efforts are focused on videos featuring young minors and we will continue to identify videos at risk over the next few months. Over the next few months, we will be broadening this action to suspend comments on videos featuring young minors and videos featuring older minors that could be at risk of attracting predatory behavior.
YouTube says that "a small number of creators" will be allowed to have their comments section remain open on these videos, but that they'll need to actively moderate comments and prove to YouTube that their comments sections have a low risk of predatory behavior.
Furthermore, YouTube's also launching what it calls "an even more effective [comments] classifier.
While we have been removing hundreds of millions of comments for violating our policies, we had been working on an even more effective classifier, that will identify and remove predatory comments. This classifier does not affect the monetization of your video. We accelerated its launch and now have a new comments classifier in place that is more sweeping in scope, and will detect and remove 2X more individual comments.