Being that I'm well acquainted with a few Amish, I'd have to say I'd far rather live between 2 Amish horse owners in a city than next to most of the halfwits with 3 scrap cars and 2 pitbulls, or one yuppie.
People seem to have forgotten less than 100 years ago, when living in the city with a carrige house and horse behind yor house was a sign of wealth.
Is it possible this regualtion resulted from someone with poor sense improperly housing a horse, and not caring about the neighbors, probably, but I doubt that person was an Amishman. I've yet to see an Amishman who didn't care for his horse properly, and keep his place neat and orderly.
Like all zoning issues, this one is just because somebody is mad at the neighbor, or some developer wants to scoop up the property cheap. Last night, I sat in town court and listened to a case brought by the town's code compliance officer because some homeowner was digging a basement below an existing house, and doing it to a depth below what is allowed. Seemed like a crock of crap to me.
To me, the biggest offenders in this issue are all the press and TV people who are sticking cameras in the faces of the Amishmen. The Amish do not want to be photographed, and usually take steps to avoid it, and this should be well known to media in the State College area.
The Amish are also accustomed to the ignorance of the outsiders, and have flourished even though the outsiders find the Amish inconvenient to live with.