The Sex Positive agenda (as advanced by some medical and psychological organizations that receive taxpayer funding) seeks to end ALL moral judgements over ALL sexual pairings regardless of sex, age, relation, martial status, or species of partner(s).
“not everything that is immoral” is a ruse. They seek to end all such notions of morality. Same as when they say “it’s perfectly natural” to explain away homosexuality. So is incest, cannibalism, rape, and a lot of other ugly behavior in the animal world.