You have that backwards. Monopolies are perfectly legal, it is only establishing and maintaining monopolies by improper conduct (ie specific anti-competitive pr

You have that backwards. Monopolies are perfectly legal, it is only establishing and maintaining monopolies by improper conduct (ie specific anti-competitive practices) that is illegal. MFNs are not per se anticompetitive, but by the rule of reason they might be under certain circumstances. The FTC would have to prove that this is one such instance where MFNs are illegal conduct.