To me, stacking and finger pinch are entirely different, though they may sometimes seem to be related, since both are more common on shorter bows.
In my experience, “finger pinch” has a subjective component to it – some people feel it more than others, even when both are shooting the same bow, with the same draw length. I don’t think there is really any way to avoid finger pinch on really short bows, as pinch is entirely the result of string angle, and any short bow is going to unavoidably have a steeper string angle. But kind of like handshock – it seems to bother some people and doesn’t bother others. So when I hear someone say that a particular short bow “doesn’t pinch,” I take that to mean that it doesn’t produce noticeable pinch for that shooter.
On a related note, a prominent bowyer recently told me that he doesn’t believe that there is anything to the notion that short bows are any less “stable” to shoot than longer ones. Instead, according to him, shorter bows are more sensitive to a less than ideal release as a result of the steeper string angle. It might be a subtle distinction, but I tend to agree, and its an interesting thing to ponder…