I can see why up-voting is useful and how down-voting is detrimental. I can see why many websites have taken decided to remove negative reactions or at least hide the number of negative reactions from the public. When people up-vote things and see the number they tend to just upvote. Same goes for down-votes, no matter how they feel about it. When other people think something is good, that likely boring sh*tty thing is seen as good.
When YouTube decided to hide the number of negative reactions, people took it badly because some things are just ostensibly bad. They failed to consider the case where if there are little to no positive reactions then the video is still bad. They also considered that YouTube appointed the community as arbiters, but were shown the reality that that wasn't the case. If a video is bad, you can comment on it why without a positive reaction. If a video is a scam, you can report it and encourage through the comments to report the scam.
Personally, I've only seen these as vanity metrics and therefore should be hidden in general. Maybe after some time has flown by show the metrics one or both.
Should they guide a trending algorithm? No. Engagement metrics with some regard to time watched makes the most sense for things people actually watch. Of course, that is game-able with watch farms. Should there be any trending algorithm? By category, sure, but a general trending. Mmm, no. I just don't believe in the idea that an all things general or popular contributes to surfacing good content since many will look to fight for placement a.k.a. game it.
Generalization is the death of all things considered good.