Also - I'm sure that somehow Elon's algos will allow right-wing bots to mass downvote freely. Some rando will say that they tweeted "Nazis suck" and within 60 seconds they had ~100 downvotes. And they'll say after they tweeted a screengrab of that - both tweets were removed without explanation.
All the science is against this. There is a damn reason every site with one has removed it.
The effect of this on twitter will be to simultaneously upset EVERYONE. LGBT people still on the site will be mass downvoted by far right. The chuds on the site will be mass harassed by the left. All groups will be upset by it.
Any large account will be able to cause a mob of downvotes with a simple retweet. The result of getting downvoted won't improve anyone's behaviour it will instead make them more hostile and more toxic.
Dislikes on videos from creators trying to build an audience is not the same as dislikes on random people's tweets. Not to mention even on YouTube the feature didn't work, because most people like most videos they choose to watch, so therefore the majority of videos that got mostly downvotes were brigaded for reasons unrelated to their quality.
The youtube dislike button did the exact opposite of what everyone thought it did (at least it DID for a significant length of time).
It promoted the video. Any end user interaction was/is considered positive for any video. Disliking a video was/is no different. Honestly not sure if it did or does much for comments either. And the whole "people will see negative dislikes and see people dislike it for some reason and hopefully learn why" might work somewhat, but is largely cope. People aren't going to look at it 95% of the time.