That's just it, though. It isn't just your own, unless you have your own private pumpout station. The hose itself is contaminated with every user since the hose was manufactured or last disinfected (if ever). The nozzle is infected by anything that touches the nozzle which definitely includes a long list of strangers. Anything that touches the nozzle is infected by the nozzle.
If it were simply one's own waste, I wouldn't worry about it. We don't poop on our boat, and urine is pretty safe. So, if it were just that, I wouldn't sweat it. But, everything on the pumpout station is contaminated with the fecal waste of an unknown number of users, then incubated in a consistently moist environment. Carts are often/usually parked in a little shed, which also keeps the environment warm.
For the entire time I worked in the ER (about 3 years), I never so much as caught a cold because I don't take on other people's germs. I'm not a germophobe, but when you know a thing is contaminated, that is different. In the ER, the saying was, "If it's moist and isn't yours, don't touch it."
The problem with the process is that it makes it extremely difficult to contain the contamination. This isn't like changing a diaper. It is more like changing a diaper on a horse, in terms of the scope of the problem. I get that you don't see a problem. That's fine. But, objectively, it is a job that presents a number of challenges that make it difficult to contain the contamination. If you are using a public pumpout, then dealing with other people's waste. And, when dealing with other people's waste, you honestly cannot be too careful. True, most of the most likely pathogens in North America won't kill an otherwise healthy person, but they could definitely ruin you for a few weeks.
Hmm ... that makes me curious. I have the equipment to take cultures from pumpout nozzles and incubate in a petri dish. I'm curious what is actually living on various surfaces. I wonder if it would be too creepy to walk around and swab people's decks around their deck fittings.