You're quite right that I don't know enough about neither that particular facility nor about how turtles in general react to being handled by humans. It might well be that the turtles are dumb and docile enough that treatment is the best option.
The question should still be seriously considered every time we think about "rescuing" and medically treating a hurt wild animal. I've seen enough "animal lovers" collecting birds after oil spills, making them go through rather extensive treatments before releasing them. The poor birds haven't only been cleaned from the oil, they've also lost the natural waterproofing of their feathers and most of them freeze to death after having gone through a rather stressful procedure.
So some times the best option for the animal is to be put out of its misery, unless the survival of the species depends on the animal going through a lot of crap. Other times, treatment is best for the animal. And it should always be a case-by-case evaluation, not a knee-jerk reaction towards one of the options.