Honestly, it isn’t hard to justify Youtube’s choices on this very specific issue. The dislike button presumably has a function beyond public shaming. I expect it’s primarily for tailoring recommendations and tuning their algorithms, but in any case it was clearly being abused by troll hordes.

If Youtube devs could see that significant amounts of dislikes were coming from users who hadn’t watched the video, or could identify other statistical aberrations, it stands to reason that such abuse would actively interfere with the legitimate functionality it was intended for and/or work against the interests of YouTube, advertisers, as well as authors and viewers.

I personally think that removing the public counter was an elegant solution in this case, as it suppresses the worst excesses of trolling while maintaining the original intent of the dislike feature, which should improve the overall experience for most users, generally speaking.