Slippery slopes abound everywhere.

The fact that you'd be crushed at a depth of (IDK, 2km or so?) underwater doesn't make "swimming" unhealthy.

My concern with eugenics is that it's a thing which various groups of extremely narrow-minded bigots push for to promote mutually exclusive ideals, ideals which often have much the same level of biological awareness as an untrained idiot picking up a scuba kit and trying to walk from London to New York along the sea floor.

If we go slowly and carefully, if these treatments are optional and not mandatory, we might be able to build a better world without such self-righteous bigots. But this is definitely a case where we want to be slow, spreading this over multiple generations if we can, because we don't know the limits of our own ignorance.