Company A can't directly increase the pay of workers at Company B. But A can increase the pay of it's own workers, making it more desirable than working for B. The increased competition on the labor market requires B to raise their wages as well. All workers win.
The equilibrium may still not end up with A and B paying the same, but personally I care more about everyone having enough than everyone having the same, so even unequal wage increases are a positive in my book.
I'm sure Amazon would be willing to pay more to well-qualified workers than to less-qualified workers. But that's not the type of argument I was responding to. The parent comment suggested that Bezos should pay his employees more simply because he can afford to.
I don't see how it's reasonable to base employee wages on the wealth of the company owner -- if Amazon stock tanked and Bezos lost a lot of money, should he cut employee wages? If not, then why should he increase wages when his personal wealth increases? It would be better for employee wages to be based on the employee's skills, not the employer's personal financial circumstances.