Joss has really created a challenge for himself here. He may not care what the fans think, but the fans do pay his royalty checks. I have no right to dictate to Joss how to tell his stories... he doesn't tell stories to order... but I do have the right to review his stories with my feet, if I find them crappy.
And right now, I've got the "crappy" sign sitting in the window.
But really, how is this any different than expecting the Bangel shippers to quit reading if Buffy were to tell Angel that she's sorry, but Spike's the man for her. If Twilight turned out to be Giles, or Xander, should everyone who loves that particular character abandon the story? People loved Jenny, Joyce, Tara, and Anya, and were shocked when they died. They loved Doyle, Wes, Cordy, and even Darla. They all died, and all of their fans regretted it, but as far as I know, there wasn't any significant loss of fans any of them died.
We all know that Angel has his own series, published by a rival company, and we also know that IDW isn't gonna end it, so the chances are about as close to certain as they can be that either Angel is NOT ultimately going to either die OR become truly evil at Dark Horse. Not the REAL Angel. So it's either some sort of a doppelganger, or he will be somehow redeemed, restored, and set back on the path of good in time to star in the next issue of his own magazine.
This is, as I said earlier, just Joss playing dirty with his fans for no reason whatsoever other than that he can do it and get away with it.