Why blame the Democrats for doing exactly what they said they were going to do? Hell, at least the Democrats keep their campaign promises.
Personally, I lay this at the feet of a majority of American voters who were willing to elect into office politicians who publicly supported the idea that gays should be allowed to serve openly in the military and would enact the policy changes needed to make this happen.
At the end of the day, the military America wants will be the one they get.
They never would have done this before the election.