After seeing this topic, I realized that I have been seeing more casual "short shorts" on men, here in ultra-conservative Utah, lately. Seems to be a growing trend, here, as well as elsewhere.
I would not be surprised if the company that makes
Chubbies helped instigate the return of the men's short short to the US. When they first launched in 2011, their motto was 'Sky's out--Thighs out!" and, I just saw on their website, today, an update to that thought, "We believe in the right your quads have to a life of freedom and sunshine"!
They are a bit pricey, but, obviously, their sales have continued and grown, contributing to men wearing shorter shorts. You may want to check them out, if you haven't already.
https://www.chubbiesshorts.com/