The way I see it, a guy like him probably had people constantly tweeting him, messaging him and leaving him comments asking him for any thoughts he had about the trailer and the casting and all that. And part of the purpose of his video was to shut all of that down. "Stop asking me about this."
Another part of it, I think, is a criticism of the pandering remakes that we keep getting. And "Ghostbusters" bombed so it looks like the public agrees.