To be fair, I would have benched JT too based on his play the entire game. Very poor on the defensive end.
in my opinion I wouldnt, you ride your best guys no matter if their having an off night and let him get out of the funk on his own, it happens all around the league, if jason comes out and isnt on his game, he knows he is not going to loose his job thus allowing him to comfortably get back into a rythm, it does wonders for a players mindset to know his role. Thats why IT comes out so jittery sometimes, he doesnt know if or when he will see the court again, it puts him on pins and needles, as it would with any player.
Now if the bad play gets extensive then you may look into demoting him, but JT has been playing great, no reason to believe he wouldnt be able to snap out of it because at the end of the day his best is still better than chucks best.