No of course not. I was just assuming, but we will never know for sure. Gender could be an issue, too. Even without statistics we can pretty much state that the majority of the online QAF fandom who creates and reads fic consists of heterosexual women.
Like I said, I don't know anything about the HP fandom but I'd assume that there are mostly women, too, but more men in general. And more variety in age, gender, personal and political background just because it must be a way bigger fandom to begin with.
Which probably leads to more specific sites for specific artists.
For example: I started writing QAF fic in German but I didn't find a really good place to load it up. As far as I know, there's only one quality site for German fan fiction but people hardly read or commented there, so I was frustrated and decided to adapt to the majority, sort of. Means that I tried to write my QAF fic in English like many others here do even if it's not their mother tongue. Um, not sure if the artists here feel underrepresented, too. We should ask one ;o)...