I believe several trends were in motion at the same time here, and to some degree, they were operating at crossed purposes; hence, there were both benefits and losses.
The period between 1900 and 1950 was a time of rapid industrialization, urbanization and material progress in the developed world. That, in turn, led to a demand for government-provided security, under uniform standards.So large, impersonal organizations arose in many sectors of daily life, and institutional living, in everything from hospitals to schools, to jails, became more common.
Standards of personal hygiene rose, to the benefit of all of us, but privacy diminished as bathing facilities were often shared by everything from athletic teams to workers in dirty jobs to school students. In all-male facilites without windows, complete nudity in swimming pools was often the rule. These changes also allowed males to indulge latent/closeted homosexual leanings without divulging their inclinations as openly.
With regard to use of the enema, this probably had little direct efffect other than within the most regimented instituions, but it probably conditioned us to talk about them more openly --- a variation on "locker room cameraderie" probably more prevalent among women.
But the pattern appears to have changed agian with the emergence of womens' liberation in the early 1970's, probably because of the tendency of the fairer, "pursued" sex to view their physical selves as diminishing assets, to be secured and protected. The growing number of female-headed, single-parent households almost surely influenced the behavior of the young men raised in them, so that "open showers" at school disappeared at the same time that grooming standards allowed longer hair styles for boys.
Again, the societal view of the enema within this trend wouldn't be too prominent, but it is worth noting that the junior-year "health" class in the high school I attended used to include training in both First Aid and Home Nursing (from a Red Cross textbook which included how to administer an enema -- with illustrations), but those who came after me informed us that the course was quickly modified after the appearence of the famous "Penthouse letters" a few years later.
"Oh, the more it changes, the more it stays the same
and the hand just rearranges the players in the game."
(Al Stewart - "The Eyes of Nostradamus")