For some even this reverse engineered clone would be unacceptable.
I could see that if it was a software emulation or e.g. an FPGA reimplementation, but this one is still using the original GPUs so would be comparable to having a modern GPU from Asus or Gigabyte instead of the reference designs from AMD or Nvidia.
It mostly has nothing to do with any technical issues. It is about recapturing a feeling for days gone by and part of being able to recapture the feeling for them is only using period manufactured hardware.
I could see that if it was a software emulation or e.g. an FPGA reimplementation, but this one is still using the original GPUs so would be comparable to having a modern GPU from Asus or Gigabyte instead of the reference designs from AMD or Nvidia.