That’s the literal implication of “bi-sexual.“ in its construction as a word

And it achieves the exact same result in terms of attraction. The whole point was that there’s absolutely nothing wrong with calling Blacksun a straight relationship regardless of whether Blake also likes girls or not. The relationship in question only uses attraction to the opposite sex to exist, and thus is an expression of heterosexuality within someone whose sexualities attract them to both the different sex (Herero) and the same sex (homo)

As for those exceptions, I thought the whole point of the term “pansexual” was to cover attraction to them in addition.