I think they are saying that there is a difference between genetic manipulation and eugenics. While the latter is the former, the reverse is not necessarily also the case. Our concept of eugenics explicitly tries to perfect mankind, through genetic modification and selective breeding. This is the actually creepy part of doing it. People deciding for other people if their genome is worthy enough to be allowed to reproduce. Utterly incompatible with our understanding of individual rights.

It is also uncomfortably close to nazi ideology, with aryan / pureblood German genes being desirable, and other ethnic origins not so much, leading to sterilizations in the „best“ of cases, ethnic cleansing in the others.

That being said, there are those doomsday instructions in the American desert, for our successor civilizations on big slabs of rock, written in pictograms. And one of those rules explicitly tells them to perform eugenics, to ensure mankind never reaches our current population numbers again, so they may never have to fight over a shortage of resources. And to ensure those humans will live in harmony with our world.

I feel like you're actively choosing not to read what I said, because literally the entire point of that post that I'm not saying that.

I'm saying banning all forms of genetic engineering is an overreaction to the Eugenics War. Not all genetic engineering is eugenics. Like any medical technology, when used wisely, it can be invaluable in helping people and improving their lives. The Earth was so traumatized by the results of eugenics that centuries later, they still mandate the entire Federation throw out the baby with the bathwater.

DS9 clarifies this a bit:

DNA resequencing for any reason other than repairing serious birth defects is illegal. Any genetically enhanced human being is barred from serving in Starfleet or practising medicine.

And in regards to the ban:

Two hundred years ago we tried to improve the species through DNA resequencing, and what did we get for our trouble? The Eugenics Wars. For every Julian Bashir that can be created, there's a Khan Singh waiting in the wings. A superhuman whose ambition and thirst for power have been enhanced along with his intellect. The law against genetic engineering provides a firewall against such men