I disagree with your first sentence about two options; if we're to give credence to the idea of a simulation, there are other options we should give, in the absence of evidence, equal weight to... maybe the universe is the dreamlike state of some being, maybe the holographic principle can be extended to encompass greater questions of existence. Just because something like "simulation" is known to us as humans living in our time, and is something we can relate to, shouldn't limit the possibilities. Outside of some reason to believe the metaphysical nature of the universe is one thing or another, there are likely infinite possibilities, including many we couldn't conceive of. As to your main point in that paragraph, I agree: it doesn't matter.

I agree that fidelity of a simulation doesn't inform us as to whether or not there is a simulation involved at all. I'm trying to point out that a simulation is a simulation of "something" external to itself at some fidelity. If that's the case, the larger reality would be external to the simulation since 1) the simulation would be a simulation of something, 2) the simulation would simply be a component part of that larger reality. This may all depend on how we define the term: "Universe". If we mean universe to mean the metaphysically complete reality, then a universe by that definition couldn't be a simulation since it would be simulating something outside of itself. If we mean some smaller sense of the word Universe, like the observable universe or the perceivable universe, then perhaps.

I think trying to explain the universe or reality as a simulation or similar is nothing more than humans doing what we have done since long before recorded history: we're projecting existence (and its "causes") onto some explainable, graspable concept with which we are comfortable. This is nothing more than the motivation that created every religion on earth and is at least as likely to be a correct vision as any of those. In the old days we created Gods which resembled us, but had exaggerated qualities and powers to manipulate the universe and act as its cause... today, we feel much more comfortable with modern concepts such as "simulation"... but we have no more justification to make that claim than our ancestors did to mysterious thunderers high up on mountains.

The question of "Is there a God?" or "Is there a simulation?" is not a 50/50 proposition. The default position is the negative: there is no God until proven otherwise, there is no simulation until proven otherwise. We can start to believe and question as evidence mounts, but right now, I don't see much for a simulation (unless perhaps you want to argue that a quantized universe is just a pixelated one as we'd see in our own simulations).

Again, the author is justified in their claim that the Universe Is Not a Simulation until there is sufficient evidence to question it otherwise.