has recieved and registered the slap he needed. That was not just a look of gratefulness that his dad would prefer him above all otheres, it was mixed with tears of shame that he had driven Finn to the point that Finn would say something so out of character for him. Kurt knew what he had done. It just may take a few cycles of denial and flogging before he admits it out loud. When you are that ashamed of yourself it is really hard to face up to.

Not that I would know anything about that.

Related to that, although the situation was unrealistically staged, those three actors did their best anyway. That was some fine acting. That was art.