That would hold if the 20's hadn't been the 'roaring 20's' after WW1, although you could take it that the message was received 2nd time round.My personal theory is that the most prudish times were actually the 50's and 60's as WWII enormously disrupted society on all levels, and then after the war everybody wanted to return to "normal"
From family experience, it was 'normal' in some ways, but it changed roles and aspirations. My parents moved from manual work to 'office' jobs, and a bigger world-view as a result of travel and skills acquired.