I think the problem with choosing the male sexualities is that there aren't as many widely appealing options. Dorian is really the only companion male with mass appeal and then there's Cullen, who has HUGE mass appeal, but is an NPC. Solas got quite a bit of steam, mostly with women, early on, but it seems like a decent amount is diverting to Dorian now that we've seen more of him. With the females, Sera, Vivienne and Cassandra have always had strong followings. It seems like there would be a pretty even spread of disappointment between males and females if any of them were gated off or not LIs. Then Scribe Girl is really cute and I think most would be happy to have her as an NPC extra. While there are more males, I think the dedicated fans for them are more concentrated.
Earlier on, I felt like it seemed strongly slanted for more males favoring Dorian and more females favoring Solas, but now it seems like just as many females and males are favoring Dorian and less overall are favoring Solas. I just rarely see people in the romance threads rooting for Solas to play for their team now. So, Dorian makes sense as a bisexual option to appease the most people, but then who will they pick for the gay and straight options that would be fair to everyone?
Honestly, I'm alright with literally any male being gay but Blackwall, if Dorian is bi. I just really don't want them to pick the "tragic soon to be dead" guy as the first ever gay male companion.