I have only read your account. So just going by that.
But with that, I think there could be a different take.
He has said before that he agrees with the jurisprudence on birthright citizenship. That is definitely the majority opinion (not saying it is right...I’m very familiar with the contrary opinion). This is current “constitutional law” (as in the majority of judges/opinions are here). He has said he agrees with it.
He is now saying that as a matter of policy it doesn’t make sense.
That’s perfectly compatible. Our current policy needs can absolutely not square with constitutional law. At that point you have to change the constitution.
That “could” be all that he is saying.
I don’t know how else you would talk about the issue, if you think that our current reality shouldn’t allow birthright citizenship, but you think that the constitution does require it. You would have to say just exactly that.
That’s my take at least, again, just after reading your account.
I posted the video link in my reply for your reference.