The problem is that Google is in the business of making money, not in the business of filtering bad from good content. Their decision to keep negative feedback hidden from both their content-producers and their visitors is quite easily justified from a financial point of view.
First, about protecting content producers: Youtubers who generate content with high viewcounts (and thus generating the largest revenue) are either in the show business (e.g., singers) or individuals who associate their personal identity to their brand (e.g., influencers). The problem with influencers is their psychological profile: the vast majority of them can be described as suffering from general anxiety disorder, depression and chronical attention seeking.
This is a very dangerous cocktail that can easily lead anyone in that profile towards suicidal thoughts as soon as anything negative or critical about their performance or appearance reaches their perception.
These people are cash cows for both Google (Youtube and ads) and all companies that use them as human advertisement platforms. Anyone with good sense would know that they should hide negative feedback from these people and make sure they keep believing that the world loves them. Their revenue depends on it.
You can find a similar models in Twitter and LinkedIn. On both platforms, an increasing number of individuals brag about their recent job accomplishments, and they now even share pictures of any training or education they get. Their user interface will emphasize the fact that you had some likes, reshares/retweets and even send you nudges to encourage you to go on. However, one thing they will never tell you is the number of people who just completely dislike what you do.
Users would be devastated at discovering that most people they actually mark as "friends" or "connections" despise everything they post online, they would feel depressed and probably engage into avoidance behaviors towards virtual social networks. And that would also drive revenue down very rapidly.
Second, about hiding the signal from users. When Youtube hides the number of dislikes, it prevents you from a accessing a crucial quality indicator that will very likely influence whether or not you will click (view) the video. What happens is that you must click the video to know if it's bad, and you will have to click subsequent videos until you find the one that suits your expectations. Two consequences:
- the view count increases --> and thus attracts more people --> more revenue
- you click more videos until you find a satisfying one --> more revenue.
That's it. Hiding negative feedback turns Youtube into a terrible experience for viewers but maximizes both short-term shareholder interests and highly vulnerable content producers.
Enjoy it, or leave it, they know you are a minority :)