Well for some of them I reckon the only reason they don't do the first one is they can't reach!
Hands down pants and eating food/touching surfaces, peeing on the toilet floors, not washing hands after the toilet and touching surfaces, smearing shit up the walls and over toilet seats, farting loudly wherever they are, menstrual products left on the floor in the toilets, wiping bogies on furniture, chewed food left on tables, chairs & floors, changing nappies on tables, fortunately I've yet to witness someone whipping out a potty, but I've heard of it happening. And maybe fleas but more likely head lice or scabies. Not to mention the colds, coughs and stomach bugs you're exposed to because people come out when they're ill and cough and sneeze all over the place and touch everything.
And that's before you get to the state some bedrooms are left in.
And this is a 'middle' place, not a rough pub, I know you're probably going to be all "Eww I wouldn't be somewhere that people did that" but the truth is that it's everywhere, you're surrounded by it. The 'nicer' places like mine just do a better job of cleaning it up and keeping it under wraps.
I don't think that dogs need to be everywhere and I'm my dogs owner not their mother, and they're treated like dogs because apart from the fact they're my responsibility, it'd be doing them a disservice to not treat them like dogs.
But humans aren't automatically pristine and perfect, some of them are downright disgusting and they do it all the more in public places because they get some kind of kick out of knowing someone else has to clean up after them. At least animals don't do that.