> They're not thinking, it's doing math, mathematical transformations of data

Whatever thinking fundamentally is, it also has an equivalence as a mathematical transformation of data. You're assuming the conclusion by saying that the two mathematical transformations of data are not isomorphic.

A simulation of information processing is still information processing, just like running Windows in a QEMU VM is still running Windows.

The Chinese Room experiment applies equally well to our own brains - in which neuron does the "thinking" reside exactly? Searle's argument has been successfully argued against in many different ways. At the end of the day - you're either a closet dualist like Searle, or if you have a more scientific view and are a physicalist (i.e. brains are made of atoms etc. and brains are sufficient for consciousness / minds) you are in the same situation as the Chinese Room: things broken down into tissues, neurons, molecules, atoms. Which atom knows Chinese?

> But a simulated mind is not a mind. This was already debated years ago with the aid of the Chinese Room thought experiment.

Yes, debated and refuted. There are many well known and accepted rebuttals of the Chinese Room. The Chinese Room as a whole does understand Chinese.

> But a simulated mind is not a mind.

How would the mind know which one it is?

Maybe your mind is being simulated right now.