How is the teaching "self-serving?"  The Catholic Church could make things so much easier on itself if it sold its soul to the popular culture (like the Anglicans, starting in 1931) and announced, "oh, well, if your intention is good and you plan on having kids (which is why you're using contraception) and you're married then it's OK."  Then the married dropped out.  Then the plan.  Then the intentions.  Then the sexual differentiation.  Drip, drip, drip.  The Catholic Church has not been "self-serving" on this topic; it has been truth-serving.