I'm also confused as to the interpretation you are making Mav. Did he make contact and impede the path to the ball? I don't understand how Westerkamp slowing down makes any difference.
I think there was contact but not as much as it looks like from that angle. There can be contact but whether it's a foul depends on a lot of things.
I think Westy slowed down before there was contact but a lot of people seem to think it was the contact that slowed him down. That makes a lot of difference in whether the contact prevented him from getting to the pass.
As I said, the rule states it's the offense's job to avoid the defense. And it Westy slowed down on his own, I'm not sure he was going to catch that pass even if there wasn't any contact.
If it would have been called, I don't think anyone would have argued against it. Maybe it was. But I definitely don't think it was as obvious as some like to think. Especially without seeing it from a different angle. We saw one angle that was nowhere near what any of the refs would have seen. It also happened to be the worst angle to tell how much contact there was an who initiated it.