They probably found that dealing with such false positives was more expensive than turning off public view of dislikes. The decision reeks of soulless bean counter thinking.
""" This is optional for creators today! But we’ve seen that when creators choose to turn off likes/dislikes on their videos, they can be bullied and harassed for their decision. Ultimately, because it’s YouTube’s responsibility to protect its community and create an inclusive environment where creators (like yourself!) feel safe to express themselves, we’ve decided to make the dislike count private across all videos, so that creators aren’t pressured to make this decision themselves. """
^^ Loosley translated >> We can't let our paying advertisers get review bombed and we have to ensure we provide them with the most value possible. We also want to phase the use of dislikes out of our algorithm for reccomendations and turn to an exclusively paid promotion model in the future but can't do that surreptitiously without removing the dislike button in advance. #ifeveryreccomendationisanadvertweonlyhavetotellyouonceintheT&C's