It's not just the fact that a senseless amount of resources go towards trying to save the above-mentioned species, it's the irony that those resources are spent in a counter-productive manner and mostly serve to further the extinction of the very species they try to save. Let me elaborate with a simple analogy. In the chicken page in wikipedia! it says that
chickens are one of the most common and widespread domestic animals, with a population of more than 24 billion. And later on in the farming section it says that More than 50 billion chickens are reared annually as a source of food, Now how is it that the very species we kill most is also one of the most common and widespread species. The pattern is worth noting. It's because of simple human economics. What's useful survives and thrives. What isn't doesn't, and at best barely survives with the help of misguided donations. Economy doesn't care whether it's chickens or pandas. The resources that are useful and profitable will grow, while those that aren't will become a nuisance and will diminish. If you allowed pandas to be grown on farms, and used as a source of food, and medicine, you'd suddenly see thousands of panda farms and millions of pandas emerging. If there'd be a regulated market on pandas we'd see people selling panda meat and bones for a price that is profitable, and as long as it stayed profitable panda populations would thrive, just as chickens do. But while pandas, tigers and other similar species remain "protected" by law there'll only be the occasional illegal killing and a limited population of them that are protected only from the limited resources that try to "save" them. Since those resources mostly come from small donations, the panda population also remains small. In other words pandas aren't a self-reliant species (as they would be if they were allowed to be owned and traded) and this causes them to go dangerously extinct. It's the same with tigers, and many other species that are considered dangerously close to extinction. TL;DR: If you want to save pandas, eat them.