Maybe individual command of space is a basic part of personeal self-determination and self-inage -- such that when too many physical bodies are in too small a space, it stirs up threats of extinction just as violence might do. The "feeling crushed" sensation brings out the lash-back reaction. No-one wants to be boxed in, or tyo be an object in a sardine-can situation -- at least not if he has a spark of self-determination left -- IMHO.

A