Since we are all weighing in on this, I'm going to add my opinion. Feeding animals is risky, but its fun. However, if I lost my thumb to a moray, I definately would not have a toe grafted on in place! Its scary looking.
If there was a reason not to feed eels, I would say the only reason would be for the eels sake. We (as divers) should well be aware of the risks. Diving itself is inherently risky. However, feeding eels, a dangerous animal, conditions them to associate divers with food. So the first time some unsuspecting divers swims by the eel, its going to pursue them, and they may end up killing the eel. That actual scenario has happened several times in the caribbean.