That's a downright silly argument. Why not bring up incest or after-birth infancticide just to soundly refute it?
Because they're not being proposed -- yet-- by certain German bishops, or popularized --- yet --- by the Political-Media Complex.
Marx and Kasper are going to be smacked down hard, and I think it's the Burke Five (Burke, Muller, Brandmuller, Caffarra, and de Paolis) plus the African bishops who'll lead the smackdown.
I can't wait.