The fact that basically all of this stuff stopped before people in their 20s were born means yeah, it's all quaint historical “ha ha things were so backwards” in tone when younger people think about it, if they even see it outside of medical museums. Not even infants get injections in their butt, I've only heard of butt injections as a fading memory of a joke of things that didn't actually happen within our lifetimes.
When trying to determine if a child is being abused, apparently enemas are one of the things asked about, abusive parents will use them as punishment, or sexual abuse, or as a way of completely controlling every aspect of their child's life. And even then most of us haven't heard of them. You've got normal laxatives and stool softeners now that work fine, combined with better diets for many people, combined with the knowledge that you don't need to go once a day, or “clean out”, with detoxing in any way shape or form outside of your kidneys and liver functioning normally being firmly placed in the pseudoscience category. I read a thing where if someone from the 70s were to instantly jump to present day and tried eating our meals, they'd shit themselves from the amount of fiber packed into everything. In the instances where diet means constipation, the doctor orders… a change in diet, not enemas to force the body to do what it would be doing if you didn't put garbage into it. I was apparently constipated as a child, and never got a single enema or suppository, or even a pill laxative because the solution was “stop feeding her the top 3 items on the ‘causes constipation in small children’ list”.
Some of the non-laxative suppositories I've seen mentioned I looked up, it was apparently for pain or fever, and whatever it was, it wasn't aspirin, and wikipedia specifically said it basically didn't even work.
Rectal temps fell out of use when digital thermometers became common. Followed by ear thermometers (the only thing ever used by the school nurse from elementary through high school), armpit temperatures, and now instant read thermometers means you don't even need to wait 3 seconds, and nothing to sterilize or discard.
I think it's more common for medical fetishists of my age to be into thing like bondage with casts and stuff along those lines, things that still happen, and happened growing up, or sexy nurse role play that just involves a skimpy outfit that doesn't resemble anything we've seen actual nurses wear, let alone being a parody of it.
Sorry for rambling, I've had a bunch of thoughts in my head on this subject.