That's a really drawn out way of saying religious people are more open-minded, because they believe things without proof. Sadly, this ignores the fact that having a religion inevitably means you must deny some or all other religions and mythos. Essentially, he has no point. This is just a feel-good passage for religious people, meant to make them feel superior to those who follow the evidence-based view of the world. This is just a man telling religious people what they want to hear: That they are more open-minded individuals because they don't need science to believe something.
Admittedly, that is a clever spin, and it comes from an author with an excellent vocabulary and a decent enough grasp of concepts to sound highly intelligent. But make no mistake, this is just fluff that makes religious people feel superior. Science doesn't make the claim that any religion is wrong, and is in fact always open to any religious claim. Science is just a constellation of evidence shaped into a view of the universe as we see it, making no claims against religious belief, but refusing to believe it without evidence. There is, after all, a difference between denying something, being open to it, and believing in it. Scientific thinking is open to everything that has yet to be proven, and this includes religious claims. There is no possible way to be more open-minded and free thinking than to take the purely scientific approach.
What the author was hoping for, and what I'm guessing most readers also believed, is that the anti-religious people (often wrongly calling themselves just 'atheists') are representative of the scientific worldview. They are not. Anyone making the claim that religion is wrong is also making a claim without proof. There's no reason to think religion has any truth to it without evidence and scientific testing, but there's also no reason to think it's false. So just so long as you don't get your head stuck up your butt and start becoming an anti-theist (people who are against religion), science is the most open-minded you could possibly be. No choosing a belief without proof, no discounting a belief without proof, and certainly no denying that "We simply don't know everything," which is true (and likely always will be). That's just the most open-minded and free thinking anyone can possibly be.