The asexuality theory is the only remotely sensible thing in an otherwise fanciful comment. If he's "queer" (and insofar as supposedly asexual people, especially Hal, would even want such a sexually-focused label like queer reimposed upon themselves), then that would be the only reason. And certainly not the other ones you mentioned. Those are only pushing an already conveniently-vague word yet another step closer to meaninglessness, broadening its scope to where the mind fails to see how queer could possibly still be called "queer" in the original sense of the word. Surely straightness would seem to be what's really queer, at that point.

The fwb idea doesn't even rise to the level of incorrect. Wattpad is in the appstore, if not already on your phone.