I considered that as I was reading her post (my first impulse as I read the first paragraphs was to argue that subtext is in the eye of the beholder ;) but in the end I found that I agree with her here. I mean, Rawles isn't saying Roy/Riza is canon (as in, they're officially together in a romantic way) but that the subtext is itself part of canon, and that this subtext here is of a romantic nature.

And that there's a difference is between 'subtext' and 'interpretation of subtext'. This difference is of course, to a degree, open to interpretation itself. Fans can always make a case for their own interpretation, and every fan will see subtext slightly differently. But I think there is a foundation to base any interpretation on - no matter where each individual fan thinks canon ends and interpretation begins - and depending on the foundation you can make a strong case for your reading, or a less strong one.

In this particular case, with all the examples in FMA canon, I honestly can't see Roy/Riza as just platonic. I mean, I don't think they're secretly together as a couple or that they've even as much as kissed in the past, I don't even think they've ever talked about their feelings. That stuff would be extrapolation and interpretation. But there are just too many factors for me to see those two as merely platonic... and I really can't imagine Arakawa intending it as such.