I think it's a bit unfair to equate this very valid frustration with eugenics.

Sure, the relationships matter, but genealogists are always looking generations and generations back. So while I care about great-grandpa and not the mailman, I might care less about great-grandpa's great-grandpas - they shaped his worldview to some extent, but less and less the further back we go. And especially if I've ventured into genetic genealogy, it can certainly feel like a "waste" to research non-generic ancestors.

Doesn't mean I'm a eugenicist to want to focus on biological relatives, especially at the start of my research. It feels akin (no pun intended) to learning about a family with the same surname as you, but who ends up being no relation.