Of course they could implement shadow-dislikes to prevent the dislikes from tabulating, but that requires more steps being taken.
Consider the ratio of views to likes/dislikes. Compare that ratio to other videos. It seems about par for the course. Also note that these videos have comments disabled.
In the absence of actually knowing how youtube tabulates likes/dislikes, this website just substitutes a guess and calls it the "real" number. Surely there could be no other reason why these numbers might change other than a conspiracy involving the deep state colluding with the communist youtubistas over at Google.
Seriously though, who gives a fuck about youtube downvotes? This kind of psychotic obsession over internet noise isn't healthy, and if you are spending a lot of time on this kind of stuff you should seek help.