Your experience is somewhat limited then. In my experience most people that dumpster dive are incredibly conscious about not only leaving a scene tidy, but also go as far as removing some* recyclable items from the trash and transfer them to nearby recycle bins; their prerogative is to reduce waste from the offset. Besides, as pointed out by @AnthonyC there is no need for dumpster diving to be a crime when the problems you’ve identified are already crimes.
*As time permits. Annoyingly, most dumpster divers realise they can get in trouble for their actions, and don’t like to stick around too long.
