I don’t think his point is that he won’t fight either way and that it is irrelevant whether we have religious freedom or not in the law. If there is persecution Christians will still share the gospel and if there isn’t they will as well. We have freedom of religion in America right now in theory but you can still be discriminated against.
It seems more to be about political non-involvement than a blueprint for a theocracy IMHO.
I think you’re right:https://www.gty.org/library/sermons-library/2326/the-believer-as-a-citizen
He actually is not advocating for a theocracy, but being content with a situation like the NT church say (which faith we need) but his denial of support for gov. ensured freedom of religion logically means that gov. mandated freedom under a theocracy is the only kind of freedom he can support, thus silencing all others that disagree with him.
Which some Catholics dream of.