@Tomoshi-chan
That's what “sexual orientations” come down to: a mind who thinks in stereotypes.
When a man say, “I am not attracted to <group>”, what he really means is that he's not attracted to whatever his stereotypical conception of said group is, this is not specific to gender but to anything else. In fact, this is what it generally comes down to when a man makes any such blanket statements about an entire group in terms of liking or disliking them.
The problematic thing with gender is that many feel compelled to follow the stereotypes of it laid out for them, however.