Yeah, I totally believe that they are gay. But it's kind of another example of it being downplayed. Here's one good modern example who could really be the gay knight in shining armor that people are asking for and it's simply innuendo in the actual text.
In the show, however, he fits it much better. They don't really hide his sexuality and it's actually relevant to the subplots.
That being said, I'm glad that GRRM decided to Word of God it. I always like when authors make it clear when it's ambiguous. J.K. Rowlings did this with Dumbledore, although he's not related to the trope!
I just found another GRRM quote about it, actually.
"Turns out, series author George R.R. Martin says the characters "are gay in the books too." Also, “I never meant to make it a mystery.” “I like to handle things subtly. I couldn’t ever actually say, ‘such-and-such is gay,’ because, as I’m sure you know, the word wasn’t invented until the 60s. And I’m talking medieval times, and I’m not going to say, ‘so-and-so is gay.’ But I thought it was pretty clear in context.”"
I've also seen quotes from him stating that the only reason there isn't homosexual sex described is because none of the viewpoint characters are homosexual. Which makes sense. It's too bad that Loras and Margery aren't more important to the story, as I've always thought they were a really interesting analog to Jamie and Cersei.
But as to the Dragon Age series itself...well, now I can't remember what I was going to say. Huh. I seem to have derailed myself. That's never happened before...