Ah. It used to be just someone that would say something so inflammatory or provoking that it would force interaction or responses from the people witnessing it.
Like an obvious joke or quote of an earworm that it creates replies. Or sometimes something rude or just wrong on purpose. Modern bad actors adopting trolling tactics is not necessarily the same thing.
You could say trolls are like onions, they have multiple coatings.
Yeah the best ones are just taking advantage of our empathetic neurons to initiate a conversation. The terrifying ones then use that opening to inject their own thoughts on others.