Why are people criticizing and blaming Mathurin for the loss?

They say he choked the free throws, but he hustled for both the offensive rebound and the steal. Even if he did make his first two, OKC would still have the ball for the last possession so there's no guarantee that the outcome would have changed anyway. The away from the play fouls he committed are usually not called especially at the end of the game, but since he had already missed his free throws to begin with, it doesn't really matter anymore when OKC is up 2 possessions.

I think my definition of choking is different from others, but I feel people are being too harsh on a bench player who played only 14 minutes that game when he was pretty much the difference maker just the game before.