I've argued rather extensively against religion on this website.

That was my impression as well, but when I went looking for those arguments, they were very difficult to find. Perhaps my Google-fu is weak. Help from LW readers is welcome.

I found plenty of places where you spoke disrespectfully about religion, and quite a few places where you cast theists as the villains in your negative examples of rationality (a few arguably straw-men, but mostly fair). But I was surprised that I found very few places where you were actually arguing against religion.

Name a single one of those arguments which is equally effective against simulationism.

Well, the only really clear-cut example of a posting-length argument against religion is based on the "argument from evil". As such, it is clearly not equally effective against simulationism.

You did make a posting attempting to define the term "supernatural" in a way that struck me as a kind of special pleading tailored to exclude simulationism from the criticism that theism receives as a result of that definition.

This posting rejects the supernatural by defining it as 'a belief in an explanatory entity which is fundamentally, ontologically mental'. And why is that definition so damning to the supernaturalist program? Well, as I understand it, it is because, by this definition, to believe in the supernatural is anti-reductionist, and a failure of reductionism is simply inconceivable.

I wonder why there is not such a visceral negative reaction to explanatory entities which are fundamentally, ontologically computational? Certainly it is not because we know of at least one reduction of computation. We also know of (or expect to someday know of) at least one reduction of mind.

But even though we can reduce computation, that doesn't mean we have to reduce it. Respectable people have proposed to explain this universe as fundamentally a computational entity. Tegmark does something similar, speculating that the entire multiverse is essentially a Platonic mathematical structure. So, what justification exists to deprecate a cosmology based on a fundamental mental entity?

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I only found one small item clearly supporting my claim. Eliezer, in a comment, makes this argument against creationists who invoke the Omphalos hypothesis

Never mind usefulness, it seems to me that "Evolution by natural selection occurs" and "God made the world and everything in it, but did so in such a way as to make it look exactly as if evolution by natural selection occured" are not the same hypothesis, that one of them is true and one of them is false, that it is simplicity that leads us to say which is which, and that we do, indeed, prefer the simpler of two theories that make the same predictions, rather than calling them the same theory.

I agree. But take a look at this famous paper by Bostrom. It cleverly sidesteps the objection that simulating an entire universe might be impossibly difficult by instead postulating a simulation of just enough physical detail so as to make it look exactly as if there were a real universe out there. "Are you living in a computer simulation?" "Are we living in a world which only looks like it evolved?" Eliezer chose to post a comment answering the latter question with a no. He has not, so far as I know, done the same with Bostrom's simulationist speculation.