I just re-watched the play in question. He absolutely DID NOT lead with his shoulder. To do that, you have to get your head to one side of the ball carrier. You also have to come to base. He did neither of those things. He leaned in and initiated contact with the crown of his helmet. If that wasn't targeting, they may as well take that rule out of the rulebook.
Edit. Even if it wasn't helmet-to-helmet (which it was), striking a defenseless receiver above the shoulders is targeting. It checked every box.