> eugenics were accepted as science
This is exactly my point.
By your definition, the “progressive” view is the one that doesn’t try to keep society the same. At some point, eugenics came around, and the world now thought this was a good way to progress. Opposing this adoption at the time, according to your definitions, would make someone a conservative.
My point is that opposing certain directions that society may be moving toward doesn’t need to be viewed as “conservative” or “anti progress.” There are certain things, like eugenics, that we can preemptively say, or should have potentially said are not a good idea. We don’t need change for its own sake.
If a progressive movement started advocating eugenics, they would be advocating a return to previous social mores - that's conservatism in a nutshell. Just because that movement also happens to hold "woke" ideas doesn't change the direction they want to carry progress.
This isn't a moral gotcha for anyone who has more historical memory than a goldfish - the problem is that most people don't seem to care to, so they come up with contrived examples like yours bc they can't keep the thread of human history for longer than a generation.