That you should choose such an off-the-wall scenario shows that you actually have no argument. I am reminded of the people who support the use of torture saying "Well, if a terrorist had a nuclear device in the city and the only way to get to it before it goes off is by torturing him". Both of you are being wholly unrealistic.

There is a difference in kind, not degree, between those who disagree with Humanae Vitae and those who commit genocide.