He's being defensive.
He knows he embellished the affect that the joke had on him. Now, being confronted with it, he's literally psychologically made the decision to fight anything contradicting his position.
He's going to continue to grow in anger the more you make him realize he's a follower who likely attached to the bullies in his high school and belly laughed at everything they said so he could be down.
It's sad, really.
This team has to realize there are just some players you don't leave. Period. In todays league you give up the 2 before the 3. A 3 is no longer a low percentage shot. I remember a sequence last night where JR's man left him (in the corner no less!!) to help on a drive. Whoever it was on the Cavs immediately kicks it to JR. I think it was BJ guarding Kyrie who then leaves him (Kyrie Gotdam Irving!) to contest JR....who promptly swings it to Kyrie who knocks down the open 3. 2 guys on 1 play left alone when that shyt shoulda been on the dry erase board before the game that that's a no-no.
Yeah, they helped off kevin love, channing frye, and Jefferson multiple times, and didn't close back out... like, yo, make them put it on the floor.