Philosophically, less "leeway" is given to offensive players, because they know what they are doing. We give leeway to the right CB for grabbing a wide receiver when the ball is thrown to the left, and the QB never even looked to the right. No call. The holding truly had no impact on the play.
But, in the case of an offensive receiver, he knows how the play is supposed to develop, and he knows he is not permitted to initiate contact downfield (if he doesn't, that's a coaching problem, not an officiating problem). He should be given no leeway in avoiding contact with the DB, even if the pass is not thrown directly in that area. If it was in the far 3rd of the field, OK - pass on it. But, as in this case, if it happens in the same 2/3 of the field where the pass is thrown, it is a foul.
Sadly, this was clearly a designed play, and designed to "pick" the DB that was to cover the player that eventually caught the pass. Sad, in that it was deliberately designed to break the letter, spirit, and intent of the rules. It wasn't accidental or incidental. I'll say it - they cheated. I'm sure their mindset is, "It ain't cheatin' if ya don't get caught."
We need to stay with our keys, especially in crews of 7. We need to get these fouls.
Robert