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.
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.
The justification for the wages being the wages is that that IS what the open market decided.
Consider what might happen if Amazon paid their workforce 5% more than their competitors instead of paying bottom dollar. Competition for that higher wage would improve the quality of their workforce (and then produce a higher quality product). Other employers would them also compete to get quality workers.