1) This strikes me as careful cherrypicking of "absurd" results to pick only the non-absurd "absurd" ones. You're supposed to say "well, giving women rights isn't so absurd after all, people who thought it is absurd were mistaken", but not all absurd conclusions from the past turned out to be okay in hindsight. Some were pretty horrible.

2) People who say "it is okay if my moral reasoning produces absurd results" generally don't personally think "that sounds absurd, but I'll accept it anyway". Typically, the result is something they are strongly motivated to believe, but which is thought absurd by others. They welcome the moral reasoning because it provides a way to reject their critics.

(In the LW-sphere, there are people who actually do accept results that seem personally absurd, but the LW-sphere is a minority. Most people don't act that way. Go tell a vegetarian that he should support exterminating all wildlife to end wild animal suffering, and see what response you get.)

3) Rejecting reasoning that produces absurd results even if we can't find a flaw in the reasoning is an important way we avoid errors.