Remove a category of packages in Gentoo

Let's test out using Gnome... I don't like gnome at all, I do thing like this:
eix -C -I gnome | grep "\[UI\]" | awk '{print $2}' | xargs emerge -pC
Or, with newer versions of eix:
eix -CI gnome --only-names | xargs emerge -C
Since eix supports category query easily, If no eix installed, then slowly:
emerge -ep world | grep "gnome" | gawk '{print $2.8}' | xargs emerge -pC
or if u have qlist, this would remove all package include 'gnome':
qlist -I gnome -C | xargs emerge -pC

mourn for gnome, Hah!