How so? I don't have any female friends (I don't have any male ones either). If I started looking for a girlfriend (which I currently don't), I would indeed be looking solely for a romantic relationship, so I don't see how having female friends would be a prerequisite.

That said, I don't think that matters for the site in question. I'm just not a part of their target audience. Doesn't mean their idea doesn't work for other people.