Okay, given the title, you can understand that I'm not sure whose side I'm on on this one.
Harlequin decides they want to set up a joint deal with a vanity publisher, and SFWA then declares that all of Harlequin's books are no longer SFWA-eligible.
I'm sorry, but I cannot get behind SFWA on this. It's one thing to say that books published on a pay-to-play basis are ineligible, and it's another to denigrate every author published by any imprint under the Harlequin umbrella. It's the height of hubris. SFWA has clarified that their defenestration of all Harlequin imprints is not retroactive, and that it can be reversed anyway if Harlequin corrects its business model to what SFWA considers professional.
Against the other side, Harlequin is simultaneously using its brand to sell self-publishing, and then NOT branding the resulting slush as Harlequin. That's pretty clearly... well, I can't say fraudulent in the technical, legal sense... but it's kind of a triple bait and switch - first, encourage beginning authors to send their works to your traditional publishing house, second,use your cachet to switch them over to your self-publishing house, and third, don't let them even use the cachet you sold them. See Jackie Kessler's analysis here.
Oh, I did think up a great and truthful marketing slogan for the joint venture: "Horizon: the place where you never arrive".