Horribly evolved? They have a pseudo thumb specifically to help hold bamboo. Do you understand? They evolved a whole thumb to help eat bamboo. If their ecological niche wasn't viable, how the hell would they have lasted long enough as a species to evolve a whole-ass thumb? Also, evolution doesn't stop. Perhaps, if it weren't for humans coming along and fucking things up, they would become even better adapted to consuming bamboo. We'll likely never know because we fucked up their habitats.

Bulk feeding is fine (bamboo is plentiful and fast growing). Low birthrate is fine (what real predators does a panda have?). Human caused habitat destruction is the sum and total of the panda's problems.