The demand for child sex is fueled by porn & fornication which in turn comes from decoupling sex from procreation, marriage, and family.
Ultimately, this has its source in idolatry and the rejection of God.
We're being shown in real-time the logical progression of liberalism. Rejection of Jesus -> Rejection of external divine authority and law -> acceptance of internal authority and do whatever I want -> acceptance of birth control -> sex is for fun -> acceptance of divorce -> acceptance of baby murder -> acceptance of child sex etc. etc. etc.
Yes, Oman was intentionally not trying to have children, but that doesn’t mean he was doing it only for pleasure. You’re setting up a false dichotomy.
He was doing the bare minimum to make it look like he was doing his job, without actually doing it. As for why he was struck dead when the usual punishment is humiliation, note that he was supposed to be an ancestor of Christ. He was “preventing” (humanly speaking) the advent of Christ through the line of Judah. That’s why God killed him, so that someone else would actually do their job and continue the line (even though that eventually came through Judah’s own sin).
I see you have to quote other people’s opinions of scripture, not scripture itself, to derive your perception of human sexuality.
The only person you are quoting is yourself.