>There's a mile-wide chasm between posting an opinion that differs from the official government line and posting something that's deliberate misinformation designed to harm people.

This is true, but almost no content would fall under your definition of "deliberate misinformation designed to harm people". That phrasing might be said to be the standard, but it wouldn't be applied that way.

Also, the quote from the YouTube spokesperson pretty explicitly says that if something is wrong with the vaccine YouTube will not allow you to say that. That would be something specific, rather than broad. I doubt that they would actually silence someone that points a specific flaw in the vaccine, but that's what their spokesperson said (read: their words are unreliable).

Now I have concerns about the vaccine...

This is how it works with modern information spread. Of course you can have concerns and you should be able to state them openly. Any doctor that wouldn't have concerns without a long term clinical study does lie.

This is what makes the mask situation so illustrative. You have the same guy who is deemed the ultimate authority saying two opposing things, so one of them must have been deliberate misinformation to harm people under these rules. You can't get on TV and say "masks are useless" and the next minute, in the face of no new data, get on TV and say "masks are the law" and somehow walk away with intention preserved and reputation intact.

None of this finicky language is ever going to amount to anything, frankly. The powers that be ultimately control what is broadcast to the masses, even if those powers change their minds.