I think this:
> The survey would have a filter for people who believe in evolution and survival of the fittest.
Just means that the survey would ask that question. I'm guessing that GP wants to check whether those who believe in the Darwin awards as well as the moral justness of evolutionary pressure killing certain people earlier that other people, would be more opposed to using modern medicine to keep people alive.
Maybe? It really depends because modern medicine is part of social Darwinism, even though it is against evolutionary biological survival of the fittest. So I could see this going multiple ways among this subset of people. I'd expect the richest of them to believe both in medical extension of life (and fertility treatments) as well as believing that only those who can personally, or societally, afford such intervention should get it. This may be the dissonance GP is mentioning.
Assuming that people being kept alive by modern medicine are better at procreation, they are indeed the fittest.
Of course most of the people being kept alive by modern medicine are old as hell, though, so they are hardly the childbearing or rearing type.
So now I'm confused as to why you brought it up?