They are not going for the "all bisexual" route.
I'm sorry if this seems nitpicky, but how do you know? BioWare hasn't said what companions will be available for SGRs, let alone how SGRs will be handled. It's possible all current love interests will be available to PCs of both genders, it's possible they won't. As far as I know, BW hasn't said anything either way.
If they have said something, and that's what you're basing your statement on, please, provide a link because I know lots of us want to know.
Though I'm straight I associate openly with LGBT people so the politics of gay rights are a big deal to me personally, but I have to agree with your point: At the end of the day, I want my characters to be able to be gay because that's part of their character.
This, very much this. I have friends all up and down the entire Kinsey scale, and gay rights is a big deal for me as well. But in the game, it really is just all about the characters I'm playing. I know that my BH has always known she's gay and never understood the concept of being in the closet, while my JK is big and strong and awkward, and how she feels about her sexuality is part of that so she needs Kira to help figure herself out. Please, BW. You wouldn't want my JK falling to the dark side due to not being able to be with Kira, would you?