Taken from the new various-artists compilation My Greatest Revenge: Flamenco Recordings, 1904-1938, the track “It Was Because I Didn’t Feel Like It” by vocalist Juanito Mojama is a poignant audio document of both autochthonic-folk music—in this case, flamenco—as well as a mysterious Spanish musician whose career has been barely tracked in other similar compilations and a handful of academic essays. …