Mattis at this point has had years to change this. He has done nothing. In fact, on his watch landnav and hand grenades have been removed from Army Basic and the pass/fail portion of the Marine Infantry Officer course has been removed. In the latter case, that the Combat Endurance Test was “unnecessarily” difficult for women has been cited in numerous sources as a significant influence on the decision to do away with it.
Remember that Mattis is an Obama General, their motto was and still is, Career before Country.