Vox Day's post appears to be an example of the moral equivalence fallacy
While not vouching for the validity of the the specific points he is making, I see him attempting to make a moral argument with a valid form. Briefly: absence of correlation is evidence for absence of causation, and absence of causation is evidence for absence of moral blame.
What you see as a "we're not as bad as X" argument, can be seen as an observation of lack of positive correlation. Suppose that a woman observes that while women commit a certain fraction of assaults, men, about equally numerous, commit a larger fraction of assaults (this is hypothetical - for all I know women do commit a larger fraction of assaults). You could interpret that as the woman making a "we're not as bad as men" argument. But another interpretation is that there is a negative correlation between being a woman and committing assault. This is evidence for the claim that being a woman does not cause a person to commit assault.
(In contrast, being angry probably does correlate positively with committing assault, which would be evidence for the claim that being angry can cause a person to commit assault.)
So that covers the point that absence of correlation is evidence for absence of causation. As for the point that absence of causation is evidence for absence of moral blame, I trust that I don't need to explain it.
This post grew out of a very long discussion with the New York Less Wrong meetup group. The question was, should a group dedicated to rationality be explicitly atheist? Or should it make an effort to be respectful to theists in order to make them feel welcome and spread rationality farther? We argued for a long time. The pro-atheism camp said that, given that religion is so overwhelmingly wrong on the merits, we shouldn't allow it any special pleading -- it's just as wrong as any other wrong belief, and we'd lose our value as a rationalist group if we began to put status above truth. The anti-atheism group said that, while that may be true, it's going to doom us to be a group exclusively for eccentric nerds, and we need to develop broad appeal, even if that's hard and requires us to leave our comfort zone.
Things got abstract very fast; my take was that we need to get back to practicalities. Different attitudes to religion have different effects on different types of people; we need to optimize for desired effects and accept what tradeoffs we must. We can't appeal equally to everyone. So I came up with a sort of typology.
The Four New Members
Annie