I'll defend Disney.
You don't see them putting out pornographic movies or movies which are "gung-ho" war. Why do you expect them to not be selective in releasing films which may compromise their image as a company that caters mostly to children and families in a politically neutral way?
I'm sure that the film will be released, just under someone else's name. Or a black market copy will end up all across the internet.
By the way, Disney owns ABC, and owns Nightline which just got censored by the TV stations. I don't see them doing this "for the Man". In this case it is their product and they can decide whether to release it or not.
And since we don't know the content of the film, it may be that Disney is worried that it's contents (the author's views) are not verifiable and may open them up to libel suits.