Similarly, you may ask, why did YouTube disable comments 2019?
According to a blog post, YouTube will suspend comments on videos that feature minors that "could be at risk of attracting predatory behavior." This measure is designed to prevent predatory commenters from gathering in the comments section of such videos.
Furthermore, what happens to deleted YouTube comments? Simple answer, yes, we do get notified, in fact, you deleting it doesn't stop us seeing it. Longer answer, you don't even need to necessarily comment on our video, if you so much as reply to a comment someone is following, they'll get the notification and if they get an email, you'll forever have that comment recorded.
Keeping this in consideration, why do my comments disappear on YouTube?
It could be that the owner of that channel has hidden your comments. You can see the posts you made when you're logged into the account you posted the comments from. If you log out and your comments were hidden, neither you nor anyone else will be able to see them.
Should I disable comments on YouTube?
By disabling comments – and ratings – you can minimize the damage these people can do. You can also ban them from commenting, but that only helps if they aren't willing to make more accounts. You want to encourage interaction in a private forum.