As with most things this is about money.
Although gays are few in number compared to blacks they have considerably more disposable income per capita than blacks.
Gays for the most part do not have dependents and there for they have the potential to accumulate wealth at a younger age than child rearing parents.
This of course is recognized by Democrats as money available for political contributions. The Democrats at the same time recognize that blacks vote Democrat on average 90% of the time and have shown that they willingly forgive the Democrats most any transgression.
So after the 2010 election the Gay coalition made it clear to the Democrat Party that they had enough of the empty promises and that Obamas continued statements of no support for Gay marige and that either Obama make good on the partys support of Gay marriage or the Gayvee train would come to a halt.
Want to know the Why of what the Dims do? Follow the money.
Blacks should wise up and understand that the Democrats will continue to take advantage of them and ignore them as long as they vote Democrat exclusively. Why should Democratic leadership do anything for Blacks that cost them support from another side of their party when know that no matter what the blacks will show up at the polls and vote a strait Democrat ticket?
Dems have also used blacks to guilt trip white conservatives into trying to get some black votes... but that's over. Our guys have finally seen the light - we're not going to get the Hispanic or black vote and that's OK with us...