Why should idea of staying chaste provoke wave of shock and awe?
Pure in Heart's message is that sex belongs in the ultimate emotional and relational context – marriage
It's a rare enough thing to live in a time when an old morality is turned exactly on its head with the result that what was once considered good is now considered bad and vice versa.
Nowhere is this effect stronger than in the realm of sexual morality. A previous generation would have been horrified at the idea of sex educationalists going into schools to teach teenagers how to put on a condom or to pass out free condoms.