Just having his girlfriend make a video explaining his startup wouldn't be an issue - but having her make that video, then submitting an article that "hey, here's my GIRLFRIEND explaining my startup" makes it off as sex appeal.
Since sexism in gaming is a hot thing topic right now, imagine if Spike TV was to advertise that a program that discussed videogames, and that they advertised as being hosted by a "woman", no names, just "hosted by a woman". That's pretty much what this submission is doing.