I disagree, but it is a judgement call, and the Leagues judgement, not mine, is that applicable. Yet I also note the League statement cites this rule near the end:

"Player Going to the Ground. If a player goes to the ground in the act of catching a pass (with or without contact by an opponent), he must maintain control of the ball throughout the process of contacting the ground, whether in the field of play or the end zone. If he loses control of the ball, and the ball touches the ground before he regains control, the pass is incomplete. If he regains control prior to the ball touching the ground, the pass is complete."

I submit that had Jennings maintained control throughout the process of contacting the ground Tate would not have had the ball at the end of the play. In particular, it is not clear from the replay WHEN Jennings contacted the ground with anything other than his feet (and thus when he should have been considered down if, in fact, he were ruled to have intercepted the pass.) Even IF the catch were intercepted (which is obviously debatable because it is still debated,) a legal strip would REMAIN possible unless/until Jennings were ruled down.