Batwoman being gay was a complete overhaul of her character from a different continuity in a crisis like event that led to some pretty cool stories.
Iceman being gay came at the end of a pretty boring and uneventful comic book run that led to a total and complete overhaul of the character while still being the same Iceman, somehow. Complete with the author writing him as a flaming homo and self-inserting himself into storylines and writing his parents as gay hating bigots not to say anything about it, just because the author went through the same.
A character turns out to be gay, and then goes on to have the best stories written for it ever = a good thing.
A character turns out to be gay and now this is the most defining characteristic of their personality while having the most boring adventures ever = not ok.