I don't get the same meaning from the story of Onan. Why doe God kill everyone that has performed coitus interruptus.
We don't know if God did or didn't back then. We only know what was recorded. Just because you didn't get the same meaning doesn't mean the fact doesn't remain.
Can you tell me why it took nearly 2000 years for only some Christians to condone Contraception? Why do the majority still oppose it? Why did the reformers oppose it? Why was Onan punished? Why do people hold the position against contraception and not simply promiscuity or infidelity separately?