yeah from the initial view, it looks sketchy because you see his hand get behind the ball.
From the top down view, it looks like he just hit the inner half of the ball.
Definitely not a "clear" foul, and one that in real time is about a million times harder to scrutinize than busting out replays from multiple angles. And Pierce said already that there was no foul. Twice he didn't protect the ball versus Kobe, and twice he paid for it. End of story.