The article is essentially about a split between militant and moderate atheists.
The preferred definition of atheism
Preferred by whom?
Actually, agnosticicm is quite different, since it involves indecision/uncertainty not only in principle/theory, but also in practice. The agnostic is actively unsure. The atheist has decided the question does not deserve active consideration, and the possibility that God might exist, although not zero, is too small to be given any weight in making practical, strategic, hard decisions.
In other words, the atheist juror is sure beyond a reasonable doubt that there is no God (and so votes 'Guilty/No-God.') The agnostic juror is not sure beyond a reasonable doubt, and so votes 'Not-Guilty/Unsure.'
Preferred by whom?
By atheists.