I think this started when Japanese people started hoarding toilet paper. There were some rumors in the social media that the all toilet paper comes from China and there will shortages. This wasn’t true as most of theirs is produced domestically. But people went hoarding just in case and then there were some shortages. And after this did reach news then more and more people went hoarding.
And now that the rest of the world knows that toilet paper might get hoarded they have to hit the stores before it’s too late.