Iinm it’s because of how thick and elastic human skin are, the stinger will stuck to human skin and the bee will have a hard time pulling it out. Some will have it unstuck and live, some will die. For animal of same size, they will pull it out just fine

Also the stinger will attach to the venom sack and not spine(bee have exoskeleton). It dies because unfortunately the venom sack is also attach to their other organ and also a large open wound.