I would have loved to see the AFP response to your attitude to airport security processes. In fact, please try it next time.... I do not think they will escort you to the nearest lounge shower suite. For extra bonus points - please repeat the stunt with pulling down your pants and ask them to look.
However, your comments about US security are pertinent to you, but not the majority of members of this forum who do NOT have Global Entry or TSE Pre - because we can't. So your comments are not terribly helpful.
As a non TSA Pre user, everything you describe about hating in Australia over the past twelve months within the US has happened to me at airports all over the country. In fact in the last 10 or so days I've flown through DFW twice and out of ATL. As usual, different policies have applied. One wanted laptops/tablets out, one did not. One wanted jackets off, the other shrugged when I asked, so I woe mine and was fine. And of course, the shoe thing - which has NEVER been a thing in Australia.
Indeed at MEL T2 (int) departures security, they wanted NOTHING out - no liquids, no tablets (and of course no shoe theatre)... so ironically to your comment above - i find Oz an absolute breeze - specially domestic (because there's no limit on Liquids etc)
Horses for courses really. You have advantage in one area, yet seemingly have a problem with following whatever the procedure du jour at terminal X is. It's pretty easy even with the differing policies - because you know, they actually tell you at the check point before going through the scanner - or you can ask (like I do in the US if it's not clear from ll the shouting at peons
). And if you have a concern with the body scanner regarding specific personal or medical requirement, one can ask to be personally wanded and go through the metal detector if need be.