YouTube says comments on videos featuring young minors are being disabled all across the platform to counteract predatory behavior. Only a few exceptions where the YouTube team will closely work with the channels to actively moderate comments. The hunt for videos featuring minors that could act as a honeypot for predatory behavior will also continue over the next few months. YouTube has also developed a more effective comment classifier designed to pinpoint comments that violate the platform’s policies besides “removing hundreds of millions of comments for violating our policies”””
Source: https://www.bleepingcomputer.com/news/security/youtube-disables-comments-on-videos-with-young-children/