Long story short: a guy named Mark Duplass tweeted something nice about Ben Shapiro, the twitter mob became enraged,
James Gunn jumped in to defend Mark (against the crime of saying something nice about a conservative), he also then tweeted a bunch of outrageous things about Ben, Ben got into a back and forth with him on twitter, Mike Cernovich then jumped in and started sharing all these disgusting tweets from James, another mob got worked up, Disney saw the tweets, James got fired.