Why are people panic buying toilet paper?

PNP (China)

I am in China, where there is no such behavior, partly because the government makes sure there are enough goods for all, and takes stiff action against profiteers. Chinese people have confidence in their government! I saw Aussies fighting in supermarkets over toilet rolls on TV, and the long queues in US shops and supermarkets with trolleys piled up full of toilet rolls and other goods.