Chatting with other YouTubers. All three commented on how my comment section is friendly and productive. Here's my secret:

I use the "hide user from channel" feature on all bigots.

That's literally it. Get rid of bigots and the toxicity drops.

They worried about decreasing interaction. When you use this feature, they can still comment. Just nobody sees it. They keep coming, watching, and commenting.

As a side note, when bigots click thumbs down. It helps you. It tells YouTube to show your videos to the opposite demographic.

Point is that you don't have to police for content. Just get rid of bigots. If you do that, even those who disagree will provide productive conversations and increase interaction.