Only the handler causes it if they do the wrong thing or don't do what's neccessary to prevent it in the first place.
I disagree. Here's my example. Suppose you have a horse towards the bottom of the herd order; and he's turned out in a large herd, and when ever you go out to catch him, a dominant horse chases him away from you? You can catch the more dominant horse first, then your own, but it's time consuming and a pain. I don't see how that scenario, very common in herds, can be ascribed to bad handling.
After managing horses and herds in lots of different ways, my preference is for small, even numbered, stable groups in paddocks together. 4 - 6 is ideal, when you get up to 8 or more, the herd dynamic tends to shift frequently enough that you have more squabbles and bites and kicks.
However, this boarding situation *could* work for you with a couple of caveats - it will work best if your horse is easy going, middle of the pack type. If your horse tends to be extremely submissive, being out in a large herd maybe pretty hard on him. It will also work best if he's an average keeper. A very hard keeper will be difficult in this situation (though their willingness to feed separately is terrific) as will a very easy/prone to foundering type.
Shoeless is great as it minimizes damage done in normal herd squabbling, however, whether or not it works for you depends on whether you've had your horse go barefoot while in work previouisly or you're committed to a barefoot regimen.
It really just depends how well your ideas of horse management mesh with the facility's. In general, I absolutely agree, the closer to natural conditions you can get, the happier and healthier the horses. Where you introduce human convenience as a factor in the equation is a personal preference.
Good luck, and hope you're happy with your eventual decision.