JJ's a flopper and chippy player himself, and was probably trying to flop at the beginning of the clip.
I can't see any way possible that that hit was a flagrant-2 though. Flagrant-1 maybe, since Barea seemed to be clearly hitting him just to hit him, and followed through with the arm. But ejectable? No way.
The only thing I can think of is that if the game is out of hand sometimes the refs will deliberately make an ejection (and let the league reverse the call later) to avoid things getting really ugly. As much as the league hates fighting it wouldn't surprise me if this was unofficial policy.