I think his point is that the body's design is irrefutable argument than all are made to be heterosexual.
This is especially compelling if one adopts a theistic perspective.
"Truth has always angered peoplewhich is why some wise sage cautioned, "Tell the truth and run!" "
In ancient Troy, some greeks left a gift. There was a man, a priest actually, roaming the city streets, trying to warn them, to tell the truth to the Horse worshipping trojans that it wasn't actually a gift.
To him and his two sons a reward was presented for telling the truth. Posiden sent two huge marine serpents to grab and squeeze the three of them and pulled to them to a wet nevermore.
The name of the man who did the warning today is not well known...Laocoon.
BTW, this is the universal reason why Christians are persecuted, and why within the Secular Humanistic faith system, all the voices are unified. Heretics there are also equally persecuted, with rare exceptions (e.g., Horowitz).