Even those who revere Leviticus as Scripture are often hard-put to explain why they consider 9/10 of it irrelevant to their own personal behavior, let alone public policy. Unless you offer animal sacrifices, segregate menstruating women, and keep kosher, I'm talking about you, too.
That's why it's actually indispensable to explain moral abhorrence of perverse sex acts, in terms of Natural Law.
It's not slighting God. He is the Author of both the Book of Scripture and the Book of Nature.
I agree. People should be scripturally and philosophically literate for such situations when objections are raised