b. A ball that touches a pylon is out of bounds behind the goal line.
There's the rule. No adage there.
If it is in the possession of a player (either airborne or touching inbounds), it's a touchdown. If it's not, it's a touchback (or a safety if A put it there).
Either way, it's not simply 'out of bounds'. It's out of bounds behind the goal line.
Think about it - how can we rule that a fumbled ball that hits the front pylon on the outside edge is a touchback? It's because the entire pylon is out of bounds behind the goal line. We treat the possessed ball the exact same way in terms of its advance - touches the pylon, then it's out of bounds behind the goal line. Behind the goal line means touchdown in this example, just like anywhere else on the goal line.
You seem to be completely disregarding 4-2-4-e
e. When a ball carrier dives or jumps toward the sideline and is airborne as
he crosses the sideline,
forward progress is determined by the position
of the ball as it crosses the sideline (A.R. 8-2-1-III and IV).
2-8-2
Forward Progress
ARTICLE 2. Forward progress is a term indicating the end of advancement
by the ball carrier or airborne pass receiver of either team and applies to the
position of the ball
when it became dead by rule (Rules 4-1-3-a, b and p;
Rules 4-2-1 and 4; and Rule 5-1-3-a Exception) (A.R. 5-1-3-I-VI and A.R.
8-2-1-I-IV) (Exception: Rule 8-5-1-a, A.R. 8-5-1-I).
If a ball in posession of an airborne (by choice) player, who dove toward the sideline, crosses the sideline the ball becomes dead by rule at that point. If it then crosses the goal line or goal line extended, it does not matter because it is already dead.
However, 4-2-4-e does say "When a ball carrier dives or jumps
toward the sideline..."
(The original question does not say if the ball carrier dove toward the sideline or toward the goal line or at an angle toward both.)
So, if a ball carrier were to be 6" from OOB but running completely parallel to the side line
and were to dive toward the goal line from the 3 yd line and be blocked OOB; it is likely that he would move in such a way that the ball would cross the sideline before crossing the goal line extended and before any part of the player's body touched the ground OOB. If this were the case, by rule it would be a
because he did not dive toward the sideline; he dove toward the goal line.