The problem with this guy's response is that it assumes the "redefine marriage" political rhetoric.
Redefining marriage would entail a wholesale change in marriage where homosexual marriages are now deemed legal while heterosexual marriages are now null and void.
This is absurd as there is no such threat to heterosexual marriages ....past, present or future.
Rather, what homosexuals are asking for is inclusion into the current institute of marriage compact. (and rights entitled thereof)