The reason guys (and it is always guys) claim someone like this to be a genius is because this is how they would like their life but haven't managed to do it. So when someone comes along who proves you can live this lifestyle and get away with it, they are declared a genius. "It's a guy who worked out how to do it" - sheer genius.

You will notice that any women out there who live a similar lifestyle are not called geniusses; they are given several other descriptors, mostly insulting. Money grabber, gold digger, bitch, slut, whore and man-eater. There are probably more terms aimed at deriding any achievements they may have had and alluding to the (supposedly) unfair way in which they became rich.