This was apparently made to remove “dislike attacks” on people. It is going with the idea of “Just consume and dont say anything”.
They, of course kept likes there. It makes the user think that there is no dislikes and emotionally makes them like the video. Dislikes should be kept because people must have freedom of speech and must express themselves.
Some people really deserve dislikes and people want to know what content is OK and what isn’t.
Currently, there is no perfect way to restore dislikes, but you can get an average.
You can install this plugin, which will estimate dislikes, but it does collect certain personal information.
In conclusion, there is no current way to get full dislikes working, but maybe in the future, there might be.