Wow .. I had no idea. I'd always assumed you were supposed to remove them from cooking because they would taste bad if eaten directly - not that you couldn't actually digest them!
Yeah a lot of different leaves don't break down well in the digestive track without friction or longer digestion periods (which are adaptations that actual herbivores have).
This is also why they (bay leaves or more generally all laurel leaves) are such a massive pain in the ass to compost in most places.
The wonders of insoluble fiber and wax coatings on leaves.
