Barry is the Ward 8 Councilman. Ward 8 is in the far south(east) of the District. The Ward 7 Councilwoman also voted against it. Ward 7 is in the far east of the District (E of the Anacostia River).
This makes total sense to me. Those are the two poorest and highest crime wards in the District. (You don't park your car in either and you SURE don't walk in either at night). There are no gays in either ward. Guaranteed. The black churches wield the electoral power totally in both wards. If you do something that the black, evangelical church preachers don't like, you will be replaced. Even an icon like Barry.