Here's the problem: Homosexuality isn't about sex, any more than heterosexuality is.
You're looking at the fact that "sex" is in that sentence three times and thinking I'm an idiot, so lemme back up and walk through this more carefully.
Whenever you see a character in Exalted who is not the product of some freaky Neomah bargain or Akshata Sexual Methodology oath-binding, it means a man and a woman had sex to produce them. Every time a character is mentioned to be married, that's heterosexuality on the page. Every time a character is mentioned to have children, that's heterosexuality on the page. Every time Harmonious Jade is attracted to Disciple of the Seven Forbidden Wisdoms and does something of dubious wisdom on account of that, with all of her clothes on, that's heterosexuality on the page. Heterosexual identifiers are everywhere in everything, without bringing the act of sex into the equation. Every reference to a spouse, a paramour, a parent, a child, tells you "look, straight people."
Kevin Smith was asked at a Q&A some years ago why he inserts gay characters into his films. He said that his brother (who is gay) had once told him that he could never really get into any film he was watching, because he never felt that he was represented on the screen—it was like he was watching events unfold in a world where he didn't exist, and it alienated him from the entire process. And Smith thought that sucked—his own brother couldn't enjoy watching a movie because they all seemed to take place in a universe that didn't include him. So sure, Smith thought it certainly wouldn't hurt to let his audience know that he knew they existed.
Exalted is pretty unapologetic in promoting a more inclusive gaming culture. If you (general you, not you) are a homophobe, and you like Exalted, you have to choose between avoiding Exalted, or learning to live with having gay characters floating around in your concept-space. We don't think that's a bad thing. And if you're gay, or bisexual, or genderqueer, or whatever, then you can play Exalted and finally have a game that comes out and says: Yes, you can be the hero, like this guy. Not the mincing comedy relief sidekick, not the one-note joke character, not the evil fat pedophile villain. You can be the hero; this story can be about you.
It's a message that a lot of people need to hear, and we consistently go out of our way to include them because everyone else doesn't.
If that bothers you, I would really strongly suggest that next time you read through a gaming book, you actively watch for any subtle indications of heterosexuality, because you will find them to be everywhere. They're invisible to you because they're the norm, but a homosexual reader is going to see them, and if he doesn't have any countersignals in there, he's going to feel marginalized. And that sucks.