What I really love is the cul-de-sac reasoning. You: We cannot show the movie because people won't want to see it. Me: Yeah, but the controversy may draw in more people than it might usually attract. You: Yeah but the controversy might also have the negative effect of people not wanting to see it.
The people who wouldn't want to see it, will likely not come and the controversy is not likely to influence them in any way, except perhaps to have them come and picket. For those who would not care one way or the other, they are more likely to be drawn by the controversy (that is an added element of intrigue) than turned off. Heck, some may come just for the principle of supporting disliked art.
This is only an opinion but I suspect the real issue isn't that people might not come to see this particular film - it is the fear of a larger boycott or picketing/protest impacting other films or even other activities of the companies that operate the IMAXs.
Confused ? You will be...