"I have no problem with gay marriage, and this is not an example of incrementalism.
Well, it's obvious that you spit on traditional morality anyway by having "no problem" with two men or two women marrying each other, so even the theory of a slippery slope means nothing to you.
To you, it's just a walk in the park on flat ground.
To those of us who don't wear moral blinders, it is worse than a slippery slope, it's a screaming nose dive.
My God, it's like we've gone back 1000 years in time...scary!
So, are you saying that the idea of a slippery slope is a moral value, and people who don't share your world view are incapable of grasping the concept? On the contrary, I understand slippery slopes quite well, and this topic isn't an example of one. As for the larger question, I see no moral objection to gay marriage, and neither I nor society in general are harmed by it. In fact, I favor it - if our system is providing a benefit to one segment of society then it had better have a darn good reason to deny the benefit to another segment.
You can blat about moral blinders all you want; personally I have no inclination to impose my sense of morality on others, and I don't believe that any moral system - however traditional it may be - is that last word for all of society...