In practice what is deemed not appropriate for all audiences seems to be videos that do too good a job of conveying ideas that the powers that be at
TheirTube Youtube do not like. Overwhelmingly, those ideas are conservative ones.
One of the great things about the internet was the freedom. It was the living embodiment of Oliver Goldsmith’s Liberty Hall:
“Mr. Marlow—Mr. Hastings—gentlemen—pray be under no constraint in this house. This is Liberty-hall, gentlemen. You may do just as you please here.”
The Tech oligarchs do not like such freedom. Most of them are members in good standing of the Left. They prize diversity, unless diverse people decide to think one iota differently from them and then they have an intolerance that would cause any of the inquisitors in the history of the Church to blush. They are offended by ideas they do not endorse, and by the very idea that people have the temerity to think differently from the way they do.