Why is Christianity obsessed with sexuality?

The cumulative effect of the following:

• Patriarchy, and its concern to control fertility and access to fertile women as tribal commodities.
• The concern of archaic Judaism to associate fertility with religious identity (circumcision).
• The dismissal of bodily desire as more base than spiritual pursuits, to be regulated (already present in both Judaism and several strands of Greek philosophy).
• The emergence of asceticism in some branches of Judaism.
• The presence of some ascetic preoccupations, and concerns over temptation, in the preaching of Jesus of Nazareth.
• The severe discomfort with sexuality and the physical world in general of Paul.
• The rejection of libertine sexuality associated with paganism (already in place in the injunction to Gentile Christians to abstain from fornication and blood sacrifices, if they weren’t going to get circumcised).
• The continued discomfort with sexuality and preoccupation with abstinence of most Church Fathers.
• The asceticism of both the Eastern Desert Fathers, and of Jerome who joined them.
• The more intellectual yet even more pessimistic outlook on humanity of Augustine.