You make an astute observation. I'd say the same thing applies to a topic like male body image.

In his book, Justin Baldoni acts as though male insecurities over body image are something new -- just because we don't have much survey data prior to the 1980s delving into men/boys with eating disorders or low self-esteem over their physiques/appearance.

As though, prior to 1979, "most" men/boys somehow had inflated self-images where they usually viewed themselves as Adonises.