“Because he comes across as authoritative?”

More because he’s neuter; sexual neutrality, in Hollywood code, reads as benevolence and wisdom. Jackson isn’t neuter (though his sexual activity, in most of the films I’ve seen him in, is only implicit), which is why he’s the first choice when they need a dangerous black man (funny or not) for the part. (Wesley Snipes is too black and too dangerous and unavailable, in any case).

Be interesting to do a close-reading on black male actors of note and how they fit in the picture: a psychosexual map of American racial morality. Also interesting how Chiwetel Ejiofor has seemingly escaped the taxonomy by being British.

Next question: do you suppose Will Smith is already in talks to play Obama?