It's always an interesting conversation because like socialism, eugenics covers a lot that normal people consider obviously fine and obviously good but don't believe the word covers that use because all eugenics and all socialism must be evil.

i.e. most people are happy for taxes to go to roads/water/power infrastructure while being dead set against 'socialism'.

The classic eugenics gotcha is filtering for genetic disease. Most people are happy with that, but then to make the question harder what if you filter out embryos with sickle cell and then are also disproportionately filtering out multiple ethnic heritages as well.

I don't really blame people if they are exposed to these technologies and see the stats that say 'yes taller people are statistically more successful', or most people consider x or y more advantageous, then say I want my kid to have as many of those advantages as possible. The same will apply with the even more extreme case of genetic engineering where you aren't just selecting for possible traits but inserting ones that wouldn't occur naturally for a couple.

That doesn't necessarily mean it should be allowed, there's plenty of behaviors that are advantageous and not even problematic for individuals to do that are illegal because if too many people do it there's a problem and so the easiest or possibly even most elegant solution is to ban it or sub types of a behavior. Especially if a sub group of people are known to abuse it, there's a difference between picking green eyes and strawberry blonde hair because you believe it'll cause shallow people to be nicer to your kid, vs choosing blue eyes and blonde hair because you believe that is the ultimate pinnacle of man.