Yeah, diet and gut health is a big variable / explanator here. Yes, humans are omnivores, but we put outrageous stuff down our throats, and it is manifested in the horrendous turds.
Back when I was young and had a healthy gut, no small thanks due to the very clean diet I ate (lots of soluble and non-soluble fiber, home-cooked balanced meals, water as the only drink), I pushed out perfect shits all the time: 20 seconds on the toilet, one perfect turd, and practically no need to wipe (but I did, anyway).
Evolution works by killing the unfit and making sure the better fit have more kids. Usually “good enough” works for evolution. So as long as humans had the brains to realize they needed to wipe their ass, and the hands capable of doing so, and necessary tools around - big leaves, flat rocks, running water, whatever- there was no reason ass-wipers couldn’t live and reproduce just as well as those with tiny butt muscles - while bigger butt muscles meant better able to run after food or run away from danger.
As for diet -yes; until agriculture, humans ate a decent mix of miscellaneous raw veggies and meat. (Meat- concentrated protein - was what gave us the extra energy to feed our big brains). Eating mostly grains is something we did in the last 10,000 years, so evolution has not adapted us to the change. And we learned to grind grains so as to free up the nutrients faster, meaning our gut does not have to adapt as much. Other than honey (which had challenges being acquired) there was no pure sugar in our diets. That change is very recent. We used to eat a lot of animal fats because it came with meat, and until maybe a century ago, overeating was only a problem for the rich…
So we’re eating some stuff our body was not really “designed” to handle.
Probably not, although if you used fresh cow manure shortly before harvest, I’d be a bit hesitant.
Chicken and rabbit manure needs to “cure” for a while before it’s deliberately used as fertilizer, and meat-eating mammal poop shouldn’t be used on food plants, either. Cat or dog poop can be used on flowers, although I’d recommend burying it first.
One of my cats did this a few times towards the end of his life, because he had a chunk stuck in his rear end. Believe me, getting it out was not fun and also involved some anal-gland discharge. They HATE it when the vet does that to them, but I understand why they do it.