I still don't get why people care about this, it's stupid that Youtube even lets you rate scheduled videos that haven't actually been released yet. That shouldn't even be possible, so I completely understand doing this to clear out the ratings, since that shouldn't even be possible anyway. As long as they don't also do this after the video was actually released why does it matter?
This explains the sudden change in the like/dislikes ratio:
Nine chances out of ten it was a bunch of bots spamming the dislike button before the video was even out and the YouTube systems cleaned out the numbers since for those votes to hold you need people to actively confirm them.
Players only have one way to express their discontentment. Thumbs down (or bad ratings). Trying to stifle people's voice using the unfamous "bot" pretext to remove the negative opinions not only is pathetic but is an utter lack of respect towards the playerbase.
Did you know SEGA recently started to block all messages not praising their greatness on their Twitter thread (ask @syberbolt) ? Are these messages posted by "bots" too in order to justify such a vile clean-up ? How can you be so naive to gulp down such crap ?