Clearly you are knowledgeable enough! You noticed that the snake was not in good condition and needed attention to deal with the stuck shed. That's all you need to say! Ball pythons should shed in one piece. If they don't the likely culprit is low humidity. Which doesn't surprise me.
The petsmart that I go to frequently is actually really great. I always stop by and look at their animals and everything is always clean and the animals look to be in pretty good shape. I never see any sad or sickly looking animals and if I did I would definitely say something since I know most of the employees. I've even stopped by while customers are looking at the reptiles and corrected them on some terrible advice they were giving people about crested geckos. Any little help is better than no help!