They were, at first, a political
jam band, a black
MC5, if you will.
America Eats Its Young, and all that. But black
rockbands got as much attention in the
60s as 3-D smell-o-vision. Remember that the
Jimi Hendrix Experience was a
British (== "cool") band, and they had God playing guitar - Funkadelic weren't so advantaged, though you might describe them as the permanent
Band of Gypsys that
Hendrix was never able to muster together. And
Sly came in through the
soul door, belying, in part, his previous work.
Later on, the party became less explicitly political and more of a spectacle - the Mothership, the extensive mythology and plotline, etc. But there was a message in there somewhere, though only George could explain it. Maybe.
See also: Parliament, P-Funk, and Parliafunkadelicment Thang.