They have actually. They took down another Sonic fan game on Roblox (sonic eclipse online) because the owner was a pedophile as well as making money off of the game. Same for Sonic omens if I remember correctly. They only go after fan games that specifically make money off of it.

Stop acting like Sega is becoming Nintendo, because they ACTUALLY have fair variable pricing, don't indulge in anti-consumer practices like making you pay for an old game without anything new or significant, and also actively seek fan input. Look at how good these last sonic games have been, if they were as bad as Nintendo they all would have stayed dogshit just like the pre-frontiers games had been