Let suppose "♥♥♥" is defined for male ♥♥♥♥ consumers as the amount of penises in a video. Straight ♥♥♥♥ is 50% ♥♥♥ because it involves at least 1 male actor; the amount of female actors is irrelevant. ♥♥♥ ♥♥♥♥ is 100% ♥♥♥ because there are no counteracting (female) actors. ♥♥♥♥♥♥♥ ♥♥♥♥, on the other hand, is 0% ♥♥♥ because there are no male actors. Hence, yuri (by extension), is not ♥♥♥.