Yeps - exactly as I wrote above: if the defender remains vertical, straight up, then it isn't a foul. But the obligation of verticality belongs to the defender, not to the shooting player (which should be obvious but yesterday I saw someone on CCN saying players must only jump vertically to shoot the ball - guess in their mind, most layups and dunks will become illegal).
Per the rules, the offensive player is not supposed to jump forward into the established position of the defender on his shot. I.E., when legally guarded by a defender, yes: The shooter must obey the rules of verticality as well.
On a layup|dunk that has no defender, or where the defender has not legally established position, an offensive player has the right to go through that space.
This is not supposed to be football. Ballhandlers are not supposed to be running backs plowing through defenders.
Obviously, but I already said that in the comment: .
Shooters can jump forward, sideways, backward, whatever - as long as the landing space is empty when they start their jump,
I never said that the offensive player can jump forward into a defender in an established legal position, but he can jump forward.