I can't help thinking that there's another conclusion here
What they are really concluding is that in order for this universe to be a simulation, it requires a whole new form of computing capability that we are not currently aware of.
In other words the simulation can only be from us in the future, or a terrifyingly more technologically advanced species than ours.
Except of course that if we are a simulation, then us in the future can't create us in the past, unless of course they have taken over the simulation and are themselves running a historic 1st person simulation game, or indeed broken out of the simulation and somehow sequestered a server for their own creative purposes. In which case they wouldn't necessarily be us, but an earlier generation of sim...
Not to mention that if we are a simulation we are not strictly going to be in the same classification system, let alone similarity of species to the programmers and engineers that created us.