When a mountain biker rides a trail I think it's good that we give way to walkers and horses (and heck depending on where you are ... bears).
That works for me, and I fully respect that there's places we're not allowed to go (yet).
Similarly, when walking, I think it's cool that we're expected to stay in the middle of the track, no matter what, and that's what I do. No matter what.
And when walking the dog, I even get that I have to pick up after them in a little plastic bag ... I don't like that, but I do it and that brings me to my question ... who makes the rules up for what horse riders should do when it comes to their droppings?
I'm not sure at all, but I'd like to think there's a solution ... I'm just not sure what it might be.