Chris does have a point to avoid the GAC for casual application developers. The problem is he over-extended his argument to say GAC should be avoided for all the cases.
Windows is inherently a sharing platform. The sharing philosophy makes Windows what it is now. And the same is true for all platform. *nix has /usr/lib, java has CLASSPATH, Windows has PATH, and .Net has GAC. Kill sharing equals suicide in today's world.