One who hears blasphemy from a non-Jew is not obligated to tear keriyah (in mourning for the desecration of the Name of God), as he would have been had the blasphemy been uttered by a Jew. Also, blasphemy only requires that tearing keriyah if the Ineffable Name of God were uttered. Plus, Rabbi Hiyya's caveat that tearing keriyah wasn't done in his day and age, because their garments would be all torn up. A new mishnah! One who worships idols -- with a long list of how one might do that. Which raises the question of how precisely one's apparent worship needs to align with the "normal" way of these practices.