Helsig calls this incredibly common radical the TASKMASTER, because it usually shows up in kanji about learning or organized procedures.
That makes sense, but I prefer to call him the DIRECTOR, as you can easily picture his imperious figure sitting on this cliche Hollywood director's chair with the crossed legs:
. . .the tallness of the chair allows him to oversee his underlings' every move, and hector them appropriately.
Lack (欠)is spreading its legs because it LACKS good manners,but the director's chair, by definition, has crossed legs.