How's that boycott going, guys?
The fact is, dominance / submission play is a normal and healthy part of sexuality for vast numbers of people, most of whom have no interest in or even knowledge of the (apparently rather bossy and rules-bound) "BDSM community", just as many people who are sexually attracted to their own gender don't much care for a "gay community" whose self-appointed gatekeepers often seem more interested in respectability or political correctness than in fun and personal freedom.
Notice too that the great majority of the audience for the movie, as for the book, is female. This should surprise no one. Romance novels featuring varying degrees of dominance / submission fantasies have been selling in the millions for years, mostly to women, in disregard of the much smaller numbers of agitated pests of various stripes who sputter that such sexuality is "against God's plan" or "degrading to women". In fact, I strongly suspect that people whose sexuality doesn't involve any substantial dominance / submission elements are very much in the minority.
(One point needs to be made clear here, for the benefit of those who have difficulty gasping it. Yes, this movie apparently includes depictions of non-consensual situations -- emphasis on the phrase "depictions of". This is a movie. War movies similarly depict violence and killing on a large scale, and some of their popularity stems from the fact that male fantasies often involve violence and heroism, and such movies provide vivid imagery to fuel and enliven those fantasies. The same thing is the case here. People who are into dominant / submissive sexuality often fantasize about non-consensual situations and even play-act them out with consensual partners. Movies and books can provide imagery and scenarios to enhance those fantasies. That's all it is. No one, except apparently the boycott-mongers, is confusing fantasy and reality.)
Those who view the great mass of humans as passive "sheeple", easily herded in this or that direction by marketing and advertising, are cutting themselves off from a valuable source of insights into both human nature and the zeitgeist. Plenty of movies and commercial products of various kinds have been aggressively pushed on the public and fallen utterly flat; people are not so easily led. (Totalitarian states dominate their societies more completely than any Hollywood ad campaign, but approved official culture in places like the USSR or Islamist Iran is usually disdained by the masses in favor of prohibited Western entertainment which they hear about only via underground channels.) When something becomes a massive pop-culture phenomenon, very often it's because it resonates with some widespread if unsuspected impulse or fantasy or concern. If you dismiss it with a barrage of buzzwords from your own ideology, you may well miss seeing something significant.
There's also a rather ugly strain of elitism in this. "Yes, I myself have no difficulty watching violent fantasy and distinguishing it from what is acceptable in real life, but the unwashed masses aren't that smart and it would be dangerous to let them see this." "Yes, my own tastes in entertainment are fully mine -- my own likes and dislikes -- but the millions of ordinary people don't know what they like and just flock to anything they see being pushed by ads and commentators all around them." Again, if that's how it really worked, Russians in the 1960s would have raved over those somnolent state-approved boy-meets-tractor epics, while ignoring the Beatles. You're not a different species from the millions, and they aren't nearly as dumb or easily-led, relative to you, as you think they are.
As with the earlier battles over gay culture, the spotlight needs to be turned around and shone on those who are now wielding it against others. People with a "deviant" but consensual sexual preference are perfectly healthy; it's those who obsessively condemn that preference, and demand boycotts or even bans of any depiction of things that make them uncomfortable, whose psychology needs analysis.
If there's one thing I hope comes of the movie's success, it's that practitioners of "deviant" sexuality realize that they are in many cases far more numerous than anyone, even they themselves, imagine -- and that they should not allow the lies and distortions and name-calling of the ignorant to shame or intimidate them.
Finally -- again, this is a must-read on the subject.