I suppose the amount of abuse directed his way became too much.
There was something cringe inducing about the way people needled him about the ending of "Lost" after the "Breaking Bad" finale, stuff like "That's how you're supposed to end a show!" I mean as true as it is, it's bad manners to tweet him that sort of thing.
I guess he was a cool figure in the geek community in the period he was running "Lost" but after quite a few cinematic clunkers he penned people seemed to have turned against him.
Twitter exists in part so people can talk about the likes of Damon Lindelof. When the Lindelofs participate, things get weird.