Going to rewind that and go thru it a few times - when it first happened the PI looked blatant and for sure. Everyone was hollering about the injustice - including the announcers - after they showed a single short replay it kinda looked like Smith got tripped up on himself and all discussion just dropped.
Who he throws the deep (or short) ball to is one of the many problems associated with him being the QB. Various other means of giving the ball to the other team + a lack or absence of respect by his team mates compound that issue. Seen enough.