I felt that too when writers were making him all-out homosexual. I can see it in his character but it also ignores the fact that he dated several women in the past. Renee Montoya too originally was straight and dated men before Rucka outed her (so to speak) which makes her relationship with Kate in 52 problematic continuity-wise because they had supposedly been in love 10 years or so ago (when Renee was new on the force age-wise) and yet that was the period when canonically she was dating men (of course the Kate Kane in 52 also bares little resemblance to the one Rucka's now writing but that's another story).
I think a lot of it has to do with putting people in easy categories - either "gay" or "straight". How many bi-sexual characters are there in the Big 2? Mikaal/Starman who is an alien (and to whom human sexuality is different than his conception of it) and Daken/Dark Wolvie (who is a murderous scary douchebag) are the only ones I can think of? Anyone else and if not, why not?