Might be a good study in a game where everybody only had one character and was locked into playing an avatar that matches their gender, but otherwise pointless.
To be fair, the game they performed their study on (Pardus) allows only one character per player. Of course, it doesn't mean the character's gender matches that of the player or that the results of this study will be relevant in any game that lets you create multiple characters.
So you're right, basically pointless.
It seems you aren't quite grasping how the scientific method works in research.
Short and sweet version:
1. Pick a research area.
2. Decide on research method / start on a brief literature review (these will play off each other).
3. Create research questions / hypotheses based on what you think might happen.
4. Do the research.
5. anolyze all the data you collected, statistics, etc.
6. Report what you found.
You can obviously say that #1, #2 or #3 was poorly thought out / designed, but trying to argue that they shouldn't have done the research because the findings were inconclusive or "common sense" is putting the cart before the horse and antithetical to basic scientific research.
The thing is, this research doesn't tell us anything new. Take this, for example:
"There s one group for whom this kind of study will be invaluable: advertisers and marketeers. That makes it potentially valuable form a commercial point of view."
Really? So advertisers didn't already know men and women think and react differently? Ground-breaking indeed. It reminds me of that one research when scientist put some hamsters on a diet and discovered that while they still enjoy six, they are less likely to initiate it. If they were on a diet for more than a week, they tended to - surprise, surprise - spend more time hoarding food than looking for six partners!
But yeah, MMOs are a great area for social studies. They just need to be conducted professionally and with good knowledge of how online games work - unlike the research presented here.