Trying to remember how many of these I have seen via places like coursera, freecodecamp videos, edx, udemy and the like.
Again google goes after spam with a bazooka instead of a scalpel - collateral damage - meh. The spammers will just edit the video before uploading and those who don't won't get the annotations.
But I get it, at that scale it's probably impossible to one by one surgery the issue.
Perhaps a link to offer information to see annotation that were removed (and the time stamp) in case important info conveyed is being removed?