How can you tell when a video contains something misleading? For example, I struggle to find quality DIY videos without the dislikes warning me away. Dislikes are a great way for the community to clean house.
I had this exact scenario yesterday trying to remove rounded/stripped lug nuts off my wheels. It would've been very helpful to be able to see if the video I was watching had 1000 likes but 6000 dislikes to know if what I was about to do was advisable or not. Yes, I read the comments and it ended up being a simple fix with the right tools, but the like/dislike ratio is a great way to filter dangerous/dumb/unhelpful videos.
Personally, I see the removal of visible dislikes as a net positive. They were used to rain down negativity and meanness on well-intentioned videos. I think YouTube is now a happier place when a kid's crappy singing video gets quietly ranked down, versus being shown to have 34 classmates (or 34,000 strangers) that hated it.
That's precisely why it was removed. Can't let the rabble have a voice. They might think the wrong things.