They got rid of the visibility of downvotes. They rewarded longer viewing times (stuff that used to be 5-10 minutes is now 20-30 minutes, sometimes longer). An

They got rid of the visibility of downvotes. They rewarded longer viewing times (stuff that used to be 5-10 minutes is now 20-30 minutes, sometimes longer). And part of it is just spammers learning to hack the recommendation system that already existed. And without the negative feedback of downvotes, people watch spam content for long enough that the spam content gets recommended to others. Shorts hasn't been around for very long, so it kind of always was terrible.