Libertarian critique of religion: it is so that a monopoly in a market leads to inefficiency and shoddy goods—ergo, if there is a monopoly in a nation’s religion the results will also be shoddy and inefficient. It follows that Christianity is the NHS of religions—it does the job, more or less, but it is a long way from what it could be in a market environment. The same could be said for Islam. Since both religions disallow any competition and operate a monopoly, both must be sub-optimal religions—I see no reason why the same principle does not apply here as elsewhere. After all, if a religion claims to have “the truth” it shouldn’t really need to fear competition from rival religions—since these will obviously depart from reality.
America does not solve this problem. To separate church and state is to create a de facto atheist state superintended by a secularised form of Christianity—all states must have their cult, and America definitely has a cult; it’s what people today call “wokeness” and was once called “political correctness”. The state will always have a cult, it’s no use pretending it isn’t there—otherwise it will operate in a hidden way nonetheless.
You only suppress the competition if you have something to fear, if you think that your product cannot stand on its own merits—the same goes for Islam and Christianity. This means that contemporary religion is much degraded when compared with that found in Rome and Greece—and that is what you would expect, since Christianity came in during Rome’s decadent period; just like the NHS came in during Britain’s decadent period. That’s not to say there isn’t a wrong way to do religion, it’s just as with martial arts—there are many effective disciplines, and also a few disciplines or badly executed disciplines that could injure you (Scientology would be a good example in the religious field—I take it to be common sense that it hurts people).