Hate to say it.. but I have seen worse (MUCH worse) and have rescued a few and rehabbed/resold the outcome of those rescues.
You probably need to look at the Ag and Markets law with regard to Livestock in your state and locality. Horses are usually considered Livestock under most jurisdictions and all that is required is feed, water and shelter. If the animals have those things and those things are deemed adequate, then you are all done.
IMO most of the horses look to be fed enough food. Most appeared to have clean water. Some could stand farrier work. Most of the shelters looked inadequate (unsafe) IMO for keeping horses. Some of the corral enclosures also looked unsafe for horses (IMO). Some corrals had little manure control but seemed dry.
It is a "self help" stable with space rented. The individual owners are who have to be gone after. You need to read a typical rental arrangement to know who is responsible for maintaining fences or shelters. Again, if it is a triple net rental agreement, the shelters can be the responsibility of the renter.
IOW's it is likely a bit more complex than politics.....
There is something about the outside of a horse that is good for the inside of a man. ~Winston Churchill
) Dinosaur Horse Trainer