Their work rules (Program and Policy Handbook) Chapter 12 states "Passengers will be offered their choice of entree first, followed by the crew" as well as a note stating something along the lines of there will not be a “CREW” or “PILOT” designator on the entree's as these entrees may be used for a customer choice first, if needed....these two bullets is why the FA's have the 'pilots get whatever is left after PAX pick first' mentality.

The FA OBM and the Policy Handbook are available for your reading pleasure on the In-flight section of Deltanet.....scroll down on the right side to "Popular Tools" and will see links to the documents.