Shouldn't someone work there that knows these 'animals'? In all fairness, the OP inquired as to the whys of his condition and quite honestly, their answer doesn't wash. If nothing else, this snake should not be displayed for sale while they are 'attempting' to nurse it to health and put some weight on it.
Ignorance is no excuse for neglect, period.... If you take offense to us letting our emotions dictate how we respond to an obviously distressed and dying snake, I'd say I'm sorry, but I'd be lying.