People bought excess of lots of things, toilet paper just was more noticeable more quickly because of it’s huge volume to value ratio, and slow restocking (in part because of that ratio, it’s not worth warehousing so there was little flexibility in the supply chain).

Once the shortage started becoming obvious it was self-perpetuating, you needed to buy what toilet paper you could when you could because you didn’t know when you would be able to buy again. The supermarkets near me at the time had no toilet paper restocked for more than three months as supplies got redirected to “higher priority” stores.