Engagement can be quite unrelated to what people like. A well crafted troll comment will draw tons of engagement, not because people like it.
If people had perfect self-control, they wouldn't do it. IMO it's somewhat irresponsible for the algorithm makers to profit from that - it's basically selling an unregulated, heavily optimized drug. They downrank scammy content for instance, which limits its reach - why not also downrank trolling? (obviously bc the former directly impacts profits, but not the latter, but still)