If Thanos had, instead of randomly wiping out 50% of all living things, he had instead in each species wiped out only the dumbest 50% what would the reaction of each avenger have been?
Entertaining for the people who are certain that they're not a member of an arbitrarily defined group. Whether their certainty is well-placed is a different problem, I guess.
I agree that discussion is important in deciding responses, but discussions like these are also used as testing grounds for gauging acceptability. It's how places like 'active clubs' recruit and promote far-right extremism, they start with gauging the response to lower-level discrimination and slowly escalate to larger acts.
And I'm sick of living in a world where thought experiments are used to casually label people as dumb, disposable, but they're ok because they mention superheroes and that makes the whole thing outlandish. Until the atrocities occur, again and then it's "why didn't someone do something sooner?".