One thing missing in many of the answers here is that Ticketmaster fees don't necessarily go to Ticketmaster. They pass on a significant share of the fees to the venue and the artists:

>In exchange for the rights to sell their tickets TM also usually give their clients a portion of the fees they collect such as the service fee/charge, order processing fee, and sometimes the delivery fee (each described below). Whether it's for the purchase of a ticket or merchandise, the portion TM keeps helps provide the distribution and access network used by fans and clients and, considered with other revenues, earn a profit. source

The artists come out better because the anger is directed at Ticketmaster instead of them. So unless they have a solid sense of integrity, they have no incentive to not work with Ticketmaster.