Something, something, dpressive chemicals, something something, addictive compounds, something, something, withdrawal, something something, why would your god allow that to happen?
I’ve had dog owners say they don’t want to carry the poop with them on the hike and they will grab it on the way out. Which at best is a 50/50 shot. I let them know of a product called a dumppouch when I see them do something like that. I carry one for garbage I find on trails as humans make a mess pretty much every where.
It depends on how much poop is in a specific area. There is a gradient. Like a little bit isn’t bad, but one you start getting piles it can be pretty bad for the area if they aren’t allowed to breakdown or aren’t removed.
On the multi use trails we have locally there are people who ride horses, but I have never seen horse shit on the trail while biking. though I have seen the dog poop bags on the side of the trail. on the hiking trails I see dog poop bags everywhere, would be happy if they threw it into the woods (without the bags, because even if they are designed to breakdown, that only in specific industrial compost heaps)