Heh, my how times have changed. In Tulsa, Oklahoma, back in 1968, PE was required for all students grades 7-12 (ages 11-17/18, depending on your birth date). In every school I went to, showers were REQUIRED, period. At the time I guess no one thought about showering in swim speedos. In fact, I'm not even sure speedos existed then.
I guess the pure shock, happening at age 11, of having any modicum of modesty ripped from you in an instant gave rise to the attitude of "just get used to it."
However, woe unto any poor sap who popped a woody in gym shower though. OH! Except for a 'star' football, basketball etc., player poppin one. Then he was just razzed in a friendly way, and if well-endowed, maybe even admired.
Of course, when I was eleven, I had no clue why I was prayin not to get a woody in gym showers. It was many years later when I accepted my sexuality.
Steve