Earlier quoted context omitted.
But monopolies are not illegal. Violating antitrust law is illegal. --- You don't violate federal law just by being the only company to sell canine banana hammocks.
Are you arguing that they aren't hurting consumers? Just look at ticket prices over the years as more and more competition was eliminated, as well as the tactics they use to control artists. You aren't going to have much luck I suspect.
I am pointing out that being a monopoly (i.e. the only business choosing to offer a product/service) is not illegal.
Engaging in anticompetive behavior is illegal. And the Justice Dept has accused Ticketmaster of doing that.