Well, the way I read it, either he's referring to Art Directors commenting on portfolios which contain nothing but realistic guns/cars/etc (in which case it's entirely reasonable to comment that their demonstrated artistic range is pretty poor), or he's actually quoting Art Directors who don't really know what they're…
It all depends on the game you want to work on and the way the particular game development studio works. If they are looking for someone who does part of the concepting and modeling on a game that contains a lot of fictional elements then not showing any concepting work in a portfolio is a bad thing. If they have good…