I think the issue you are probably running into is a lot more nuanced then you are portraying it to be. Whether you are religious or scientific or some mix of both, creating offspring is a pretty fundamental instinct that is very deeply ingrained into humans. Logic might say "If you have a genetic abnormality you should stop procreating for the greater good of society/your potential offspring/yourself". But we aren't wired to think that way. We think of procreating. The percentage of people who want absolutely zero offspring at any point in their entire life is really tiny. People want children and will put themselves into great levels of harm to have them. You can't really fight that. Children make us happy.

The reason people tend to think of eugenics and concentration camps and such is because they don't know where your slippery slope leads to. If someone with huntington's disease should not have children for the greater good, what about people with a family history of cancer, or a family history of heart disease. We find people with a tendency towards weight gain less desirable, should those people also not have children? What about people with baldness? It seems absurd but maybe they also aren't all that desirable. Where is the line where we say "You are desirable enough to have children"? And if we draw a line, do we need to enforce it? I mean people with huntington's disease certainly cost society a lot without bringing as much benefit. Should we force people like that not to have kids? Where do we lay that line in the sand and say "this is for the greater good!"

To me, I entirely understand why people give you scorn for your opinion. It is a slippery slope and it goes against a fundamental human instinct that brings joy and happiness regardless of the overall cost, pain, and suffering.