Nice discussion.
The main reason for my interpretation is rule 2-19-2-c. To me it is simply easier (and in my opinion more precise).
If "point of intentional forward movement" = start of pass. Some of the complications of this situation is removed. This way you "only" have to see if - and where - the passers hand moved forward. The "point of release" is more wishy-washy.
However, I only use this interpretation for the situation Warrenkicker described. In situation with a pass parallel to the goal line. In those situations things like intent of the play is a better tool. At least behind the line of scrimmage.
I havn't completely wrapped my brain around a situation with a pass on the run - like a kick return. But I would have to go with "parallel or not". Which I think is what you suggested.
It seems I use the same rule in to different ways. I can only explain this by the diffence between rules 2-19-A and 2-19-B. In A the neutral zone is not mentioned. In B it is mentioned.
That's about the best I can do to explain my thinking. But at least this discussion got me thinking.