The difference is that Medders wasn't a defenseless receiver when he was hit, he caught the ball and turned upfield, so they only could have called targeting if the defender used the crown of his helmet, which he obviously didn't. The hit on West he was a defenseless receiver so all it took was contact to West's helmet regardless of if it was a helmet, shoulder, forearm or whatever from the defender. Lomax wouldn't have avoided that ejection even if he had his head up, he didn't even contact him with his own helmet so I'm not sure why that would even matter. His ejection was all about contacting the head of a defenseless receiver.