If Crabtree didn't try to fight through the contact and sold the call I felt like he would've gotten it or if the pass was a little closer. From image 5 Smith was going straight for a hug and he had it on Crabtree until the end of the play. Crabtree wasn't going to even have a shot at moving if he didn't push off since he was bear hugged. Crabtree's arms were never fully extended though which I think is the main indicator where you would see an offensive PI. We shall disagree on this I stand by my statement that I doubt you will ever see offensive pass interference in that instance and a defensive flag would be thrown on most occasions especially since the game is geared for receivers.
If the Cowboys were part of that no call at the end of the game you better believe there would be like 50 threads here complaining and it would be valid. This could be applied to any team Ravens included.