Most people who have a religion, have it because they were taught it as they were growing up. Like any generality, this one has numerous exceptions. Some people grow up without being taught any particular religion, but as adults adopt one on their own. The very idea of questioning one’s religion presupposes a certain mind set and array of critical thinking skills, which many people simply do not ever acquire. So the simplest answer to the question posed is just “it depends on who you are and what interests, and critical thinking skills you have”. Questioning one’s religion can be superficial or it can be deeply involving. Martin Luther made a life career out of questioning the Catholicism in which he was raised. For him, this questioning was an all-consuming life occupation. Most people have neither the interest nor the skills to seriously question their, or any other, religion.