This really goes against everything Star Trek stands for! It would make the end of Discovery's first season look like the pinnacle of ethics in comparison.
I mean, as I said upthread, one of the central tenants of Star Trek is no race is inherently evil/bad. We may look different, but we are all "human" metaphorically speaking. Any time that it initially looks like a race of "bad guys" are rotten, we find out the underlying story is more complex, or they have understandable motivations, or it's just driven by out-and-out racist fear.
For the Zhat Vash to actually be justified in their blanket fear/hatred of all synths, it would basically mean that Star Trek is saying prejudice is a good thing. Some beings might look just like us, but they can't be trusted because they can become devil-spawn who seek to kill us at any moment, so we should just genocide them to be on the safe side.
Considering Trek often speaks in allegory, this would be essentially endorsing the anti-semetic "Zionist" conspiracy theories in Trek form.