A year ago, I published the anthology, Forever Families. I wrote a ten thousand word short story divided into nine parts to be included in the anthology. A few months after the book came out, I uploaded the story to Amazon KDP and added the first six parts to give away as freebies to see if I could build up a fan base. I didn't succeed.
A couple of days ago, on a country walk with my husband and brother, I told my brother that I would not be writing the full story (conversation prompted as we walked by the old cottage where my grandmother died in childbirth).
He asked me to explain my decision. I said that the Internet attracted people who are interested in viewing pornography in one form or another. These Internet users are a ready made audience for erotic fiction, which is why it sells so well online. My brother said, "Ah, the 50 Shades seekers." I said that the readers of my story are not likely to even go onto the 'net, and he agreed.
In all probability, the magazine turned down your story because it isn't sexy enough, or it simply did not attract enough readers.