Twitter is certainly the worst because of the format that drives "low quality" interaction between users. Everybody is yelling at each other, in the hope to garner a few new followers or likes. To me it's definitely the most toxic social network, far ahead of Facebook or even Reddit.

Yet driving that outrage up is what gets Twitter eyeballs thus revenue, so there is an incentive for that platform to generate this sort of behaviour. Twitter absolutely loved Trump presence, they made good money out of him.