What is a catch? Inbounds or out of bounds?

[DJ's left nut]

Originally Posted by RedinTexas

One of my favorite aspects of this is the difference between a toe and a heel. If a player catches the ball and drags one toe from each foot in bounds before they cross out of bounds, that is a catch in bounds. However, if a player catches the ball with one entire foot down in bounds and the second foot touches in bounds with the heel, but the rest of the foot then comes down with just the toe out of bounds, then it is not a catch as it is out of bounds. It doesn't matter that the heel came down first, only that the toe touched out of bounds.

This is absolutely the strangest one.

Why does a toe tap where the heel comes down as part of the step OOB mean no catch whereas a toe drag doesn't?

That one seems especially arbitrary. Why should popping a toe down and lifting it be good when popping that same toe down and dropping the heel down isn't?

Best argument I have is that the toe and lift thing demonstrates a level of body control; it's a concerted movement. Whereas getting the toe and rolling onto the hell is more of a concession to momentum and thus doesn't end the first movement but is rather a continuation of it?