Well here's the thing. What the full faith and credit clause means is a matter of constitutional construction no? It doesn't mean every state law applies equally to all America that would be nonsensical. What it does mean is that states must respect other states rulings, records, etc...
So why pass a federal law attempting to interfere with this as a matter of constitutional law? For the record when push comes to shove it will fail (but it has bought a LOT of time and will continue to do so to the point where the political process may ultimately deal with it first)...the point stands though.
If 3rdnlng wants to say what he says...then he should be willing to say "I do not support DOMA." B/c remember we aren't talking about a hypothetical law supporting gay marriage...we're talking full faith and credit on that end. On the other end...we are very much talking DOMA.
Well now we're getting into if being gay is an immutable trait. If we really want to explode this topic...this is how it's done.