"Novice, Occasional, Frequent, Expert"
Expert? :V
It's relevant because these are self-assessment categories. e.g. people who ticked "expert" consider themselves "expert" gamers. And those types of people are much more likely to be the ones playing idiotically nerdy games like DF.
I shall now use this as an example of how you can make statistics say whatever you want them to say 
- If twice as many men play on PC, and Dwarf Fortress is only on PC, there's no twisting of logic to say that all else being equal, twice as many men as women will end up as Dwarf Fortress players. "Playing on a PC" isn't a gender-bias, it's just the raw numbers.
- If three times as many men consider themselves non-casual players as women, and being a non-casual player is a good predictor of liking obscure genres such as Ascii roguelikes, then you'd find that this skews the numbers 3:1. These are self-reported numbers too. I'm not calling women casuals, they self-report as casuals much more than men.
- If a game has a violent theme, and about twice as many men prefer games with a violent theme, then that would also skew the numbers 2:1, all else being equal. Again, this is about a thematic preference each gender self-reports, and not any assumption about what men and women should like.
- any independent factors would presumably be multiplied together. If you look at the data, then calculate the amount of male "non-casual PC players who like violent games" it's about 12 times the number of female "non-casual PC players who like violent games". And I'd argue those demographic groups form the core of potential DF players.
Those are all very broad things, however. There are also issues with self reporting, and the broad groups involved (men and women) are likely to skew things too. Are women less likely to report indulging in masculine behaviours like gaming, for example.
It doesn't say anything about independent games, nor ASCII games, nor genre, nor how likely people are going to go out of their way to try something different. You may find hardcore gamers are more inclined to play games like DF, but that doesn't mean they will, or go out of their way to find it (I found DF through a roguelike database thing)
Then there's consideration of joining the forum, too, which was what encouraged you to go to the stats. I don't think all the DF players are going to join the B12 forum, and even then, DF isn't the only game that Toady has made. So... yeah. I think it's reasonable for someone to say you might be interpreting stats to suit your argument.