I'm really sorry to see this, Dennett! It's a ridiculous decision. As you note, it's in keeping with how they've treated their poets and other short-from writers and illustrators. I don't honestly know what they expect to gain from it all--what they believe the advantages are. But that doesn't make it any easier when it hits the publications you've built with your own effort and poured so much heart into.
Please do keep us informed if you decide to move your work! I'm certain many of us will want to follow your photography and writing regardless of which platform you happen to be using. :)