The rhetorical force of your initial statement came from an accusation that one could not be consistent in denouncing gay marriage while accepting interracial marriage. Once you add additional assumptions, or rely on claims of fact that are true in the one case but false in the other, that does not hold. "Your argument sounds a tiny bit like something that was used to argue for something wrong" is not a good refutation.
As an aside, it looks like the quote is misleadingly truncated in a way that substantively changed the meaning. That said, the full version is still flagrantly factually inaccurate, so the reasoning above remains unchanged.
As an aside, it looks like the quote is misleadingly truncated in a way that substantively changed the meaning. That said, the full version is still flagrantly factually inaccurate, so the reasoning above remains unchanged.