That or these ableist opinions and pressures are an ethical flaw we will judged for in retrospect by a more advanced society.

Or perhaps applauded when the fascists win and all members of the ever growing categories of "useless eaters" are purged from humanity.

And no, it is not unethical for people to point out that these decisions are based on ableist or eugenicist thought.

What a strange leap of illogic, that it is immoral to challenge ableism and eugenics because someone's feelings might get hurt or they might doubt their own beliefs.

If the individual is fine, on review, with basing their decisions on internalized ableism or racism or whatever that is obviously their choice, but they should be made aware that that is the choice they are making.

A rational and ethical individual has an outright responsibility to bring it up, if only so the individuals in question can at least question the pressures leading to their decisions.