You have a point, but so does Mad. So, games have very fun audio and carefully composed music, and other audio, but there is compression to the source files already. That's why I often point out that Dolby surround isn't really a big deal, the nuances of uncompressed audio aren't in the game's files anyway. So, there comes a point while gaming where you can't really dig out any more detail/resolution, but you can pay more for a different flavor to the sound.
Mad writes these reviews so people have a sense of the headphones' sound characteristics, but higher end headphones are better suited to people who have already heard competent headphones and figured out what character they might like... Gamers who are new to headphones are better served by a competent Mid-Fi headphone, and use that as a reference if they decide to get deeper into the headphone hobby. The K612 is a very satisfying headphone, so are many of the other Mid-Fi champs. This is my suggestion, however some people will be content with monitor speakers and some people will just try to jump straight to their idea of "best possible."