I use the bidet every time I go to the bathroom for a #2, but the analogy you share doesn't really make much impact. The arm is in close proximity of the head and face, it's "there", but the anus is hidden and "far" and this some may feel unbothered with a non-immaculate routine.
The analogy also falls apart in that I also wouldn’t just run some water over my arm either lol. I’d use some form of soap and water, possibly even anti bacterial given the subject matter.
We have a long hand scrubbing routine, I’d expect similar for my arm at the very least.
