There isn't any need to say goodbye to democracy consider we are not one. I know you we wish the nation would regress back to the times where state could belittle and diminish the rights of those they deem unworthy but those days are setting. It seems marriage equality is here to stay despite all your efforts to slander and malign gays. I am sure you'll continue to predict that the sky will fall while the rest of us chuckle as your irrational views on gays get discarded on the trash heap of history.
Gays don't have special rights. They don't have the right to tell the majority "we are going to dissolve the mother/father model in marriage to children's collective detriment". They just don't have that right. The states have the right to allow that or not. But the fed cannot tell the state, "you have to let this deviant sex cult gut the definition of the mechanics of mother/father in marriage".
And BTW, which of the deviant sex behaviors aren't allowed to marry? Polygamy allowed right now to marry? No? Why not? Because they're repugnant to the majority? Because you say so? How about incest? No? Because they're icky too?
This goes into legality, equality and precedent. And it is IN FACT a slippery slope. It is not a theory. It is a matter of fact in how the legal system actually operates. Anywhere there is a dead marriage law in a state, polygamists may legally marry alongside any gays allowed to do so. Any objection to that would be legally arbitrary and the clerk denying that license could be sued and would lose. Guaranteed.