I had a similar experience earlier this month (Nov. 12) in New Orleans, but at least the AA gate agent gave an explanation, which (airline lurkers please note) does wonders to soothe the frustration.

The inbound flight from DFW that would turn around and take me and the other passengers back was delayed by the storms that were causing so much problem in the middle parts of the U.S. that day and arrived nearly two hours late. The ground crew was clearly doing everything possible to turn the plane quickly, and at the start of the boarding process the gate agent announced (paraphrasing, not quoting) that to speed boarding they would not be preboarding their Executive Platinum, Platinum or Gold AAdvantage members. He apologized for that, said he knew it was an important benefit for many of us, and said that he hoped these elite passengers understood the situation and would be willing to wait and board when their row was called in order to enable AA to get us in the air more rapidly.

I wouldn't have thought that pre-boarding the elites adds that much time to the boarding process, but I guess they feel it does.