Because 99.9% of twitch problems, and bad press, from the last few years are focused on people using Twitch as an onlyfan funnel. I would cut them out asap.
That just doesn't seem demonstrably true but I'd love to see some citations. My recollection is that Twitch's biggest issues have been regarding gambling and high-profile bans for misconduct e.g. DrDisrespect or nudity from streamers who don't even have OnlyFans accounts.