the pace of the NFL game is beyond human capacity when it comes to referreeing.......
people can argue based on who the want to win, but realistically, there are so many plays where there can be a multitude of flags thrown or none at all and they're all right or they're all wrong....
the 4th down play with crabtree in the endzone had no right answer......except one which doesn't happen......you could argue for both offensive and defensive PI and play the down again, but the league will never do that.
unless the defender simply tackles the WR, they're never going to call PI on the defender as long as the WR is pushing off or otherwise using his hands. the contact was mutual, and just because there was more contact on the part of the defender doesn't change things......as long as the contact is mutual, they're going to let it go