I know this isn't your point but I did find their sources. The first author was endorsed by the Pope apparently.
First quote: https://www.amazon.com/Global-Sexual-Revolution-Destruction-Freedom/dp/1621381544
Second quote: https://digitalcommons.brockport.edu/cgi/viewcontent.cgi?article=1006&context=hashtaghistory
Maybe they didn't want to cite them because they actually didn't make them up and pointing us to Christendom's literature would stumble us.