I think it can be defended. Anything can be defended. Putting kids in cages can be defended, as can any other atrocity over the past 4 years. It just takes some soulless bastard who thinks it’s right. “Defending” something, in this case, is just empty rhetoric designed to make yourself feel better.
It’s empty rhetoric when we’re talking about, now, a 6-3 conservative bend to a court, a court that is the sole arbiter of what a law says, what it means, and even whether or not lower courts can consider a given argument when a matter regarding that law comes before them.
If they decide Obergefell was incorrectly decided, that’s it. Gay marriage is over in the United States. I don’t think they will issue so sweeping a ruling as to un-marry the currently married, but if Barrett and four others decide it’s over, it is.
So, who cares what you think you can bring to bear to ‘defend’ it when it’s up to those six people to decide whether or not you can bring ANYTHING to bear at all?
Now, if you want to add seats to SCOTUS, you can do that. If you want to make new law that is specifically exempted from judiciary judgement, Congress can even do that.
But, until and unless either of those things happen, there is no “defense” for these issues when taking them up with the people who literally decide what the law is.