The simple answer is that the money they make from the sale of counterfeit masks is greater than the amount they lose from the hit to their reputation. Amazon h

The simple answer is that the money they make from the sale of counterfeit masks is greater than the amount they lose from the hit to their reputation. Amazon has established a de-facto monopoly on general-purpose online shopping, so they don't have to worry about people going elsewhere. They also have no legal liability, so they have no incentive to spend more than a token effort combatting their massive fraud problems. It's simple business calculus.