Because it's my comment about this book, and comment box on HN invites to write comments about it. Just because you're not okay with the topic I've chosen, it doesn't mean I should focus on your topic in my comment. Plus, I didn't write that it's neutral to me; I've written that I'm not judging if it's a good thing or a bad thing that this book has LGBT content in it. At the same time I'm not really fond of having my imagination fed with pretty graphical descriptions of two penises rubbing against each other. Do you allow me to have that preference (or absence of this preference)? I can imagine I'm not the only person that isn't interested in content like this, hence the comment.
It's a similar situation when after reading George R. R. Martin's "Nightflyers" I've noticed that the author doesn't give much info about any character, but he did focus about sexual preferences and sexual fitness about practically everyone. I couldn't care less about someone's sexual fitness. And in this book, sexual encounters were heterosexual, it still isn't right for my taste of aesthetics.
Are you satisfied with the answer?
Damn, such systemic bias against non-gay person is astonishing. People downvote and don't even understand why.