It sounds the way you say it as a bit extreme to me.
But, I'm not a germaphobic either. I would not do it the way he did.
Still, I don't wear gloves when dumping my tanks. I just wash my hands afterwards.
I don't use my freshwater hose to rinse out my drain hose. I just don't rinse it out. It gets rinsed out by my gray water that I dump last.
I wash my hands OFten with soap and hot water ! I don't smoke. I eat a balanced diet containing a little bit of everything.
I get sick less often that anyone else I know. I still do get sick, we all do. But, my lifestyle seems to work for me.
Have a nice Day.