This looks like another one of those plays like the Tuck Rule play - to all appearances and common sense it's BS, but by the strict letter of NFL rules, it was correctly called. All too often in cases of contested possession, it comes down to whoever has it last. Tate had hands on the ball, before and after landing in the end zone, it never touched the ground, so it does not matter what the Green Bay player was doing.

If a fumble can go to the player who pulls it out of another's arms at the bottom of a pile (when the first one to have it should be down by contact), then a catch can be ruled a similar way. It doesn't matter how much the one player tries to wrap his body around the ball - in replays, Tate's left hand appears to be between the ball & Jenning's chest, and he was holding the ball enough that if he was the only one touching it, it would have been ruled a catch, therefore what Jennings does is IRRELEVANT. All that matters is what the receiver is doing.

You can dispute the legitimacy of the rule, and the interpretation, but the referees followed the letter of the law.