I think nearly anyone and everyone who has boarded somewhere has seen horses whose care they would find lacking, in one way or another. Since where I ride, the horses live outside 24/7 no matter the weather, ANY kind of all day stalling feels wierd to me. But, to someone else, seeing our horses out in the rain and snow, they must think we have rocks for brains to leave them out there.
My point being, it's not uncommon for us horse people to judge each other's care standards. You might find yourself on the being judged end of that equation at some time. It can happen.
I do agree that it seems like a sad situation for the horse, and unfortunately, there is not much you can do since horses are "owned" by humans and subject to their whims. For your own protection, just tread very lightly becuase these kind of things invariably come back to bite you in the rear. Ask me how I know. (meaning I have made this mistake myself)