You folks remind me of those home buyers who purchase a home next to a long established airport, then bitch about the airplane noise.
The PCT was designed from the start as a joint use hiker / equestrian trail. The long-established rule is that horses have the right of way. Protocol is for hikers to step off the trail to allow horses/mules to pass. You don’t need a spooked horse or mule on a narrow steep trail.
Managing a large pack train on steep sections of the PCT is an interesting challenge. Expecting horse crap to be packaged and removed from the trail is naive and probably an opinion of someone who’s never been there. Hell, conditions are so sparse at PCT altitudes that the soil needs as much fertilizer as it can get.
I’ve never done the horse / mule thing, but all the cowboys I have run into have been great folks who really care about the backcountry.
In the backcountry of Sequoia / Kings Canyon, there aren’t any bikes - and in doing two-week loops on or near the PCT, you can usually count the pieces of trash - candy wrappers, tp, etc - on one hand.
booger