There is a lot of plastic waste your not allowed to put in the recycle bin, such as plastic wrappers for food.
I'm pretty sure I've heard they just can't deal with grease from food in the recycling. (Not that they don't try to address a bit of it, but that any significant amount ruins their batches or something.)
(1) Is it actually worth the water? Especially in somewhere with a water crisis, like (say) California?
(2) Can they actually wash these though? On a large scale, how could they possibly wash plastic wrappers that can cling to themselves so as to remove all the grease?