Earlier quoted context omitted.
I'm not an expert but I'm pretty sure the definition of "straight cunts" is that they aren't turned on by lesbians.
I think that the GP must not be American. I noticed in Ireland (at least) the word "cunt" is used to describe an unpleasant/objectionable person in general (regardless of gender) whereas in the US it's a derogatory term for a woman.
In one corner of the matrix is a heterosexual woman and in the other corner is an ill tempered gay man.