I don't think it will shut down crypto youtube channels only the advertising at the beginning. If their content is about crypto they are only giving their option on the matter. So it's freedom of speech. The same as facebook did it was only for paid advertisement.
Exactly, there is a difference between "promotion" and "talking about thing you are interested in". I think youtube crypto-reviewers will be the last to fall - if they indeed fall, because there cannot be restriction on what to discuss in an open forum. If anyone proves, that some reviewer promotes (instead of reviewing) ICO, then he may also fall under ban. At least that's how I read the situation.