I'm just pointing out that the breakdown of your analogy yields more fruit than the analogy itself.  Yes, we have learned a lot more about sexuality and morality over the last few thousand years.  Certainly, the new law given by Jesus is seen by Christians as an enhancement or fulfillment of the old law.  Matrimony becomes a full sacrament only in the last thousand years.  The unitive aspect of sexuality in marriage is seen as equal to the procreative aspect only in the last hundred years. And yes, we are still learning scientifically. Some advocate that learned truth can change old guidelines; others insist the old guidelines are by definition perfect. Our history shows that our perfection is overblown, and that we learn and grow as described above.

To answer your last question: I have read the passage and I believe its message, but your interpretation of its message doesn't reflect the love that Jesus offered and offers.