When the ball is on the ground a player is allowed to block/obstruct an opposing player from getting to the ball with the body, it's called boxing out and completely legal, the ref was wrong and a bad call.
Here's the rule, in its entirety:
q. Detaining: Detaining an opponent at any time by holding or pushing against her body, clothing or crosse with an arm, leg, body or crosse. A player may not hold her crosse in such a manner as to restrain or hold back a player.
You have the wrong sport for "boxing out". That's basketball.
The rule states holding and pushing not getting in a players path to the ball, it happens all the time on draws and balls going out of bounds and never gets called. Unless the offending player actually restrained the other player the call should not have happened and that was the case, the Navy player got in the BC players way that is not detaining, she did not push os hold the player back with her stick.
How about the terrible call today with MD, player drops the ball and falls to the floor with absolutely no contact at all, turns the ball over but is rewarded the ball anyway, complete momentum shift to MD on a bad call. If there was a turning point , that was it, and attributed to a bad ref call, something needs to be done, add 2 refs, every game has video, let the table ref watch the feed so maybe he can overturn such bad calls that happen every game. It's no longer the rules or the players hurting the game it's the refs and the NCAA for there win-action to correct a gleaming problem.
