I believe it is in their contract to get a meal equivalent to the highest class of service for flights that meet certain criteria. Before the merger, I was on an MKE-MSP flight and the FA's had crew meals!
I think the pilots get them with flights longer than 5 hours or international flights that return to the U.S. (i.e. ATL-CUN-ATL), as well as all transoceanic flights. The FA's probably have a similar stipulation in their contract.