Why don't single women vote?

Possibly because they are tired of being treated like addled-brained, boy-crazy, shoe whores. Why vote? I mean (giggle), it's not like you'll meet men at the polls! *sigh*
Well, it's too much to ask that Democratic politicians actually promote feminist values that might attract single women to the polls, so we might as well keep adding to the tired stereotype pile. Of course, there is the obligatory paragraph about how most single women aren't as shallow as the rest of the story will argue that they are. Nice.
There is a little noise that suggests that the male-dominated nature of politics might have something to do with why women feel excluded.

"They represent the rigid kind of male authority that single women have basically been fighting against their whole lives. And it's that male authority that has proven to be in their experience intrinsically false and suspicious," Bushnell said.

Good point. However, it's more than just the image of male authority that works on single female voters. After all, we are smart enough to know we aren't sleeping with or living with whoever we vote for. But since politics are dominated by men, it's very easy for women-specific issues to either be forgotten or disdained, the latter a particular problem with this administration. After the President truimphantly signs a bill according what your womb might hold more value than your entire personhood, it's easy to conclude that there is no place for you in politics.