The natural consequence of “postbiological humans” is effective disempowerment if not extinction of humanity as a whole.
Such “transhumanists” clearly do not find the eradication of biology abhorrent, any more than any normal person would find the idea of “substrate independence”(death of all love and life) to be abhorrent.
This solves nothing that could not be better solved by freezing development of hardware, which would also slow down evolutionary setups.
This also allows for more time for safer approaches such as genetic engineering and biological advancements to catch up, and keep us from Killing Everyone.