So, just how "hazardous" can a tank full of poo be?

I've used gloves before depending on where I'm dumping. We camp at a fairgrounds every summer and by the end of the event the dump station looks like 300 people used it in 2 hours. Sad.
Otherwise I rarely even glove up. There's a science to it, and after 10 years in ems, you learn everything washes off. (And nothing kills you).
I've even managed to keep the caps for my sewage setup, so even if I don't perfectly rinse, it's not going anywhere.