I saw the play. It looked like Harden stepped into Artest and Artest semi threw an elbow/semi was celebrating but I don’t think he intended to elbow the guy in the head. It looked (giving him the benefit of the doubt) that he was trying to push by him. I doubt he is that stupid to elbow someone that hard in the head.
In the slo-mo, I didn’t see him even look at Harden to make his a target. Having seen enough sportsmen making savage gestures after a play, I think it was an accident. The second clip is even more innocent.