These sorts of sexual themes have existed going back into antiquity, and as long as the adults involved are consenting with each other, then if they want to "play rough", that's there business.
If it doesn't suit you, don't consume it.
There are, in fact, movies which are magnitudes more vile than any of the tame stuff depicted in this film.
If you want to discuss depravity, then some of the films already mentioned far exceed 50 Shades. Movies like The Devil's Rejects, the Hostel series, and countless other self-indulgent "torture porn" titles make 50 Shades look like a Disney film, I'm sure.
What passes for "art" nowadays is really astounding. But I wouldn't ban any of it. True Freedom has many challenging and annoying side effects, but that doesn't mean we should settle for anything less...
Pretty sure you’re the first one here to mention banning anything. “True freedom,” as you call it includes the ability to call crass garbage what it is.