People hate democracy because they hate losing. Eliminating the dislike button doesn't just kill the metric of how many people hated the content, it also kills the invisible metric of (willing) abstentions.
Now that it's gone, youtube can be much freer in how it serves content, because there's no hint to whether something's terrible or not other than watching it. Google can just serve the content that it likes for its own reasons (maybe the content resembles the content it sees itself focusing on in the future, maybe they're just getting more money for the ads.) Their only limit in suggesting shitty content is whether you'll leave the site, and with personalization all they need is a casino slot machine algo to reliably keep you from doing that.
Now that it's gone, youtube can be much freer in how it serves content, because there's no hint to whether something's terrible or not other than watching it. Google can just serve the content that it likes for its own reasons (maybe the content resembles the content it sees itself focusing on in the future, maybe they're just getting more money for the ads.) Their only limit in suggesting shitty content is whether you'll leave the site, and with personalization all they need is a casino slot machine algo to reliably keep you from doing that.
Banning downvotes is like banning shortselling.