I recognize "humans are machines" is often shorthand for "biology follows the same physics as everything else", there is no elan vital, etc, but imo there's still something lost here

a machine, in typical usage, is an object designed and constructed by a deliberative intelligence for a purpose, which is what evolutionary theory states living beings aren't

the machines we currently conceive and manufacture also lack many structural features common to biology

in biology a single component may have many functions, some of which may interfere constructively or destructively, while in engineering it is often considered best practice for each part to do one thing

organisms self heal, subsist on/in an ecology of other organisms, and are resilient to informational errors

forms of computation resilient to bit level errors could be said to mimic biological antifragility, but they run on an extremely fragile physical substrate which requires constant tending (by organisms) to keep entropy at bay

even if our implements were as autonomous and resilient as we are, it still feels valuable to preserve a clear distinction between objects, which all agree may be understood solely as a means to an end, and subjects, who (in kantian form) are ends in themselves

this is not to say designed objects could not in principle become subjects, but to claim e.g. there is a clear path to sentience for deep learning models is for now speculative at best, and until we have good reason to believe a tool may develop subjective experience it can be a dangerous thing to personify it, and in any case we ought not compress ourselves into its image