It makes even less sense then, if he's really retired. Dallas should have either gotten their signing bonus money back or placed Orton on the reserve/retired list to retain his rights. If Orton really wanted to retire, then he shouldn't care whether or not he's on the r/r list.
By cutting him, Dallas keeps nothing.
I could care less about Orton, but this move on top of the Ratliff move last year makes the Cowboys look weaker.
When Orton gets "talked out" of retirement and comes back to play for some team later this season, it will be just as humiliating as playing against Ratliff was last year.