I've been saying it for decades, no one believes in God more than an atheist, because with them, it's personal.
In terms of what they're saying, perhaps it's that most people are born into a religion, so therefore it's more automatic, less thought oft put into it; whereas atheism is a more involved process, and while it may seem more logic-based, some of its stances can take an almost devotional approach, a rather fervent attitude that can seem not unlike a religious one,,,