This is only "Mostly" true for the original 1-50 Storyline and companions included therein. You have to realize that the devs made each character with a possible romance, only sometimes giving them multiple options. This issue isn't something that is easily resolved now. (Considering the layers of dust that have accumulated on the antique 1-50 Storyline.) However, I think they've been incredibly fair with newer content. Though I would've loved the chance to romance Arcann on a female Sith. Dominate that little bastard.