To claim that the Universe is a simulation means that it would be the result of some computation. Depending on your interpretation, this could mean one of two things: that the Universe does ITSELF compute, or that there is some "computer" which carries out a computation resulting in the Universe. The second is what I think the parent commenter is thinking about. In that case, where does this "computer" exist? It's certainly not in our reality. This would imply that there is some meta-reality that contains the "computer" which computes, and thus creates/contains, our reality.
If this isn't infinitely recursive somehow, then there must be an instance that is not a simulation. This is the uber-reality he speaks of.
It all depends of the definition of gods, like I said, if it's omnipotent, omniscient, omnipresent, etc.. then I feel like we can consider it our god which would include the one that made our simulation. That would means that they would respect that definition of gods towards us. In the same way, nothing stop gods from having gods themselves. I don't know too much about gods but don't some Greeks gods had some sort of power over each other? It's all relative in a way.
I'm also not actually believing it's the truth too, I'm just acknowledging the possibilities. I don't believe usual religions because I find it hard to believe their "why". The computer simulation does have a why that I believe could be a possibility.
