Comic Book Resources called Comic Book Legends Revealed that tries to take old rumors and examines whether they're true or false. In the most recent one they looked as a rumor involving Doomsday.
COMIC LEGEND: DC changed Doomsday’s origins after protests from mental health organizations.
Now apparently when the death of Superman story first hit, Superman editor Mike Carlin described Doomsday as being “like an escapee from a cosmic lunatic asylum." Seems like an innocent enough comment to anyone who isn't an easily offended pussy, but advocates of the mentally ill had a shit fit. In fact according to the above mentioned Comic Book Legends Revealed, someone actually said “If someone who is ill is going to kill Superman, how about an escapee from a cosmic cancer ward?”
Well, Mr. Unnamed Politically Correct Dumbass, the reason an escapee from a cosmic cancer ward didn't kill Superman is, and I'm not a doctor here so correct me if I'm wrong, cancer doesn't make you kill people. Being fucking insane however, has been known to do just that. There's a reason nobody ever pleads 'Cancer' in a court of law when facing murder charges.
This is actually an attack comics, and especially DC, often face. Apparently because some villains are 'crazy' that's offensive to the mentally ill. Now I know most mentally ill people are not violent criminals, but a clinically depressed guy who stays in bed all day isn't going to make for an interesting issue of Batman now is it? Of course these are the most extreme cases imaginable, it is after all a visual action based form of fiction.
Now in the above mentioned article the writer claims this is false. That DC didn't have an origin in mind for Doomsday at that point. Hmmm maybe, but I bet you they had an idea. And then there's this.
So was this a case of DC being bullied by the P.C. police? Or just a coincidence?