To the editors: Reading Huebner’s article (10/29/93) on the “swashbuckling” Hector Duarte and his murals we are told of his (Huebner’s) “awe” at learning that Duarte had been enrolled at the Siqueiros Mural Workshop, we learn that (of Rivera, Orozco, and) Siqueiros was “the most radical of the three, aesthetically and politically . . . […]