Bloody Bay is spectacular. 2 boats from Brac plus the 2 or three LC dive boats along with private divers usually adds up to about 50 people in the water. Throw in the Liveaboards and the number may exceed 50. The area is large enough to support the number, but people tend to flock where other people are. It's human nature. I doubt there is a nicer dive than Bloody Bay in the Caribbean, but you will see a bunch of divers there on a calm day.