While Scalia's point may be historically correct, it is in no way a justification for upholding DOMA. Indeed, even if DOMA's sole purpose was to remain true to history, its effect was to deprive gay couples of rights and privileges enjoyed by other legally married couples for no other reason than that they are gay.
Evangelicals can crank up the fire and brimstone all they want, but it's not going to work. Young people know lesbians and gays. They know that the anti-gay propaganda videos are biblical baloney, they know that "gay cures" are bunk and they know that LGBT people are just like them, differing only in sexual orientation.