There are a lot of conservative gays and lesbians out there who vote for Democrats because they fear the GOP's anti-gay agenda, are insulted by the GOP's anti-gay rhetoric, and have had it with the GOP's gay-bashing pols. Say the GOP went to gay voters and promised to do no harm—no FMA, no more culture war nonsense, no efforts to block gay people from becoming parents—while at the same time pointing out that the Dems haven't done much good. That argument won't peel lefty and progressive gays and lesbians, a.k.a. the majority of gay and lesbian voters, off the Democrats. But it might convince conservative homos that they can safely vote Republican, blunting the Democrats' advantage with small-but-significant chunk of the electorate. (There are more gay and lesbian voters than Jewish voters.)
Of course Democrats could—or could have—prevented the GOP from making inroads with conservative gay and lesbian voters by making good on their promises to gays and lesbians when they had the chance (see: 2009). But they didn't and it's looking they won't be able to for a long, long time. So now the GOP can sweep in and argue, "You know in your hearts that the Democrats are never going to end DADT or pass ENDA or do anything about DOMA or help unite transnational gay couples. But we will cut your taxes along with everyone else's. So vote for us and maybe one day you'll be able to buy a $4 million condo in Chelsea too."
Some gays and lesbians—the selfish and deluded ones who don't see the bright and shining link between reproductive rights and gay rights, and who can't see that the GOP's divisive attacks on the "other" are an outrage even when the GOP moves on to attacking other others (gays in 2004, immigrants and Muslims in 2010)—might be taken in by the slogan, "GOP: No harm. Democrats: No good."
UPDATE: Let me be clear: I don't want the GOP to pick up gay votes and I have no intention of voting Republican myself. Ever, ever, ever. But if Dems are worried about gay and lesbian progressives sitting out this election and the GOP managing to pick up the votes of gay and lesbian conservatives idiots, well, here's how you stop that from happening: MAKE GOOD ON SOME OF THE PROMISES YOU MADE TO GAY AND LESBIAN VOTERS. That refrain again: ENDA, DADT, DOMA. Don't throw us a fucking cocktail party. Throw us a fucking bone.
Pelosi: "'Don't Ask, Don't Tell' I'm quite certain will be a memory come Christmas."
There's just 113 shopping legislating days left until Christmas, Madam Speaker.