Having had close on five years to work out why Atheists were shown in a Pew Research Center survey to know more about religion than theists and in particular, Catholics, Mark Shea, writing in the National Catholic Register has come up with an 'answer'. To be more precise, he's come up with an excuse:
The reason atheists did better is that, being at war with all mankind about the thing that matters to it most, they oppose all theists and are wary of the whole broad spectrum of religious belief...
So that's that then. The only reason to investigate and learn is to wage war. It's not to discover the truth or anything like that. But of course:
Christians, in contrast, can hold up their end when talking about Christianity, but have never boned up on Jewish, Mormon, Islamic, or Hindu teachings since, well, they're Christian.