I often wondered if a need to sell advertising space and user data led to reddit pushing content that catered to anger, outrage and fear, as it drives engagement.

I suspect it did. There have been studies on the general phenomenon, although I don’t know of any that focused on reddit in particular.

There will always be obnoxious jerks, of course. With Lemmy, though, there’s no profit motive behind promoting them, and no algorithm that’s biased in their favor. Without a profit motive, there’s no reason to hand assholes a megaphone.