The FA typically uses the beverage cart to block passenger access to the forward lav so that the pilots can open the cockpit door and use the lav. The beverage cart must block the aisle to prevent any passenger from forcing their way into the cockpit while the door is open, taking over the plane, and crashing it into a large building or other object.

The passenger has the option to use the aft lav or midships lav, or hold it until the pilot is done. He does not have the option to kick over the beverage cart and punch the FA. In view of the prior incident involving this same FA, I would suspend judgement on this incident pending additional information.