It is the mark of an educated mind to be able to entertain a thought without accepting it. – Aristotle
I think that in that quote lies a key difference between an atheist and a theist.
Theists like Christians and Muslims are actively deterred from entertaining any kind of thought that might contradict what they believe. This is accomplished by having an all-seeing, all-knowing overseer who can and will convict and punish you for thought crime. The punishment of eternal torture and a flawless prosecutor who knows everything you think is a fantastic deterrent to entertaining thoughts that might lead to doubt.
Not being willing or able to rationally evaluate an opposing thought – like a religious claim – from the perspective of another person, is a very blunt way to avoid changing your own mind.
Entertaining thoughts that might contradict what you already believe is a cornerstone of science – scientists actively search for thoughts that might contradict established theories, even – sometimes especially – their own.
The ability to entertain a thought and examine it from multiple perspectives without necessarily accepting the premise of the thought is a mark of an educated mind and a mature philosophy because it demonstrates a lack of fear for new ideas, a solid understanding of – and trust in – your own position and it implies a willingness to change your mind. Conversely, actively avoiding entertaining opposing thoughts demonstrates a fear of those thoughts and implies an unwillingness to adapt to new ideas.