What we see here is a defender controlling the ball until he is touched down in the end zone. We can see where the ball and the receiver are separated.
Fair enough. To the extent to which "control" and "catch" are two different terms (in order to have a catch, you have to gain and maintain control under certain conditions), I can see how you can argue that because Jennings had control first, and never lost it (although he may have had joint control through the process of landing), this may be ruled an interception.
Even so, the call is definitely less egregious than it's made out to be (or that I thought it was, at some point).