Re: One of the YouTube channels I watched got its comments deleted in this manner
"...and this would stop anti-vaxxers, flat earthers, people with political opinions funded by unknown sources, and undesirables of the sort mentioned in this articles rocking up and ruining otherwise perfectly fine stuff."
That would be one of the worst things that could happen to this world.
Sure, some anti-vaxxers have issues - others point out that vaccines have caused problems in the past - not all and not often, but it has happened, and of course there's the correlation (not necessarily causation) with certain conditions such as ADHD appearing to have higher prevalence today (of course, 50 years ago we weren't so ready to label kids as having such things).
Flat-earthers are a weird bunch in general, some with some very oddly strong views. OTOH, it's a joy to watch the videos of the ones who do break free from whatever it is that ties them down, eg one who really did take up the challenge to check a few things himself and quickly saw that the earth must be such a large ball that it appears flat to the naked eye but over a few miles you can measure the curvature.
But the biggest issue I have with your post is the bits about "undesirables" and "political opinions funded by unknown sources".
Not too long back people like me were considered 'undesirable', worthy of life-long imprisonment, or torture under the guise of 'treatment', or even execution. Some still hold this view today. My crime of course is 'preferring sausage to tacos'. With your idea, people who have a differing view of what is 'right' would never have the hope of being released from the hell that has to be endured when one is of a persuasion that is not currently fashionable. Not only would we not be allowed to speak, but those who could speak up for us would be silenced as their political views would suddenly be suspect and as they 'must be funded by unknown sources' (no matter how much the person in question says they did it themselves without funding), they must therefore be removed.
There is absolutely NO reason to remove or attempt to silence someone's 'political opinions' regardless of whether they're funded buy some disliked large corporation, a body of criminals, or done by themselves with the cheapest low-quality camera they could afford. It doesn't matter if they're advocating for the rights of men to screw whatever children they fancy, or for the rights of the rest of us to execute any many who we even remotely suspect may once have looked at a child with suspect motives, freedom of speech is something that must be protected. And no, if a private organisation dislikes someone and doesn't want to give them a place to speak then that is the right of the owner of the venue to turn away whoever they wish, gay, straight, paedo, flat-earth nutjob or whatever.
The right to speak your mind, to support who you wish, and the right to hate whomever doesn't meet your fancy - we should all have this right to like or hate, associate with or distance ourselves from whomever we choose for whatever reason we wish. Just don't deliberately harm someone in the process.
Now that's over, I'm off for a hot cuppa and a lie down.