What does the fact that they voted, or didn't vote, for something have to do with anything?
Is not each bishop responsible only to the Pope?
Cononically? Except for minor decisions regarding church discipline, they have no role and no authority whatsoever. They are an aberration in the history of the Church.
None.
Basically, it's a discussion club or debating society where bishops discuss the meaning of church documents. The USCCB seems to have been modelled on the DNC, the ADA, or the ACLU. It's a kangaroo court dog&pony circus with buffet dining. Aside from the photo-ops and the quiche, it has little if anything to do with Catholicism.
Under Bernardin and during the '80s (Reagan era), there was some political flexing for cameras on nukes and socialist pieties, half in nostalgia for Vietnam-era social protest. The sodomy scandals have sort of quieted things down. No serious Catholic takes the USCCB seriously. It has about as much to do with the Catholic faith as the DNC.