The underlying issue is that those tickets have a "no resale" provision that doesn't apply when the original seller acts as a broker.
Do other brokers, when they go and work around that limitation break the sales contact? Maybe. The legal system would churn an answer in a few years.
Do AXS et al with their "only we are allowed to engage in a secondary policy" are abusing their monopoly on original sales? The legal system would churn an answer about the legality of this in few years, but I think it's obvious they at least break rules in the spirit.
Do other brokers, when they go and work around that limitation break the sales contact? Maybe. The legal system would churn an answer in a few years.
Do AXS et al with their "only we are allowed to engage in a secondary policy" are abusing their monopoly on original sales? The legal system would churn an answer about the legality of this in few years, but I think it's obvious they at least break rules in the spirit.