This news is all over the nerd internet. Here's Rob Bricken's summary at io9:
J.H. Williams III and W. Haden Blackman have announced they'll be leaving as the [creative] team on Batwoman, citing DC's editorial interference and in particular, the publisher's refusal to allow characters Kate Kane/Batwoman and her partner Gotham City police officer Maggie Sawyer marry each other.
When this iteration of Batwoman was created, the media went crazy over the fact that she was a lesbian. Except for the typically loud (but proportionally very small) right-wing blog response, the feedback was almost entirely positive. (The character even won a GLAAD Award.) The comic has bobbed along on mostly positive reviews for years now, but this will probably mark the end of that good will. In a post titled "Heartbroken," Blackman explains the situation in a little more detail:
Unfortunately, in recent months, DC has asked us to alter or completely discard many long-standing storylines in ways that we feel compromise the character and the series. We were told to ditch plans for Killer Croc’s origins; forced to drastically alter the original ending of our current arc, which would have defined Batwoman’s heroic future in bold new ways; and, most crushingly, prohibited from ever showing Kate and Maggie actually getting married. All of these editorial decisions came at the last minute, and always after a year or more of planning and plotting on our end.
DC Comics has been in editorial turmoil for years now, and that turmoil has been made public most often in the form of upset creators leaving titles with very little warning. There's even an internet clock called hasdcdonesomethingstupidtoday.com, and it's updated with alarming regularity. But maybe DC's biggest mistake in recent years was soliciting a Superman story written by hateful homophobe Orson Scott Card, and the lesson DC seems to have learned from that controversy is: Don't make any waves on LGBT issues at all. Don't be pro-gay. Don't be anti-gay. Just don't make waves.
Good luck with that.
I stopped reading DC's superhero comics soon after they relaunched the entire line. It was too stupid, too creatively void. I liked Williams and Blackman's Batwoman comic, but I quit reading it because I knew it wouldn't be long before editorial bumped the two from the book. I figured they would get bounced over their refusal to take part in some stupid crossover or something, but this is even more disappointing. Fuck DC Comics and their repeated lack of support for the gay community. It's now officially a trend.
UPDATE 2:54 PM: DC Comics released a statement saying they are against marriage for these characters, not just gay marriage:
As acknowledged by the creators involved, the editorial differences with the writers of BATWOMAN had nothing to do with the sexual orientation of the character.