You're assuming that clans have some kind of general rule about joining them, and that implies that there's some kind of conspiracy of the leaders of all the great clans to exclude certain players based on hidden criteria that only the Bilderberg Clan knows about; and the end result is nothing short of a campaign of mass genocide with anyone less than these requirements, leaving only an elite few to enjoy the privileges of playing Crysis 2 multiplayer uninterrupted by lower forms of life. That the Hashish-ans predicted the establishment of this game's multiplayer several centuries in advance and that every incarnation of the Illuminati thus far has been keeping the tradition of making an elite few the best clans in gaming history, even when gaming wasn't around yet.
That explains everything.
No, but really, it depends on the clan. There's no blanket requirement.
Personally, I'd invite you into mine if I had one, a 3.0 K/DR is pretty awesome (I have the same stats
)