The population is for the most part self-segregated. This is different than a political separation or an institutional segregation like slavery or Jim Crowe. It is the way most societies interact. They tend to socialize with people that have various common traits. It may be race, language, history, nationality, culture, sexual orientation, or religion. In the USA we tend to think of ourselves as all inclusive but that is far from the case. We band together in our little groups and ignore the others even to the point of political bias. The greatest divide, however, is religious isolationist. Now, this comes in many forms, from the David Koresh commune type to moron subculturalism.
For many years religious sects in America have tried with a great deal of success to cut themselves off from the "secular" world. The idea here is that if the religious leaders can control what their members are exposed to, they can control the entire sect. They way they dress, what they eat, how they are educated, and even how they think.
A particular concern of mine is what they read. I can say that I am well read even though I am not as avid a reader as I should or want to be. What I am saying is that my reading is universal. I love reading murder mysteries, but my library includes science, philosophy, classic literature, history, biography and books on other topics. I even have books on mythology and theology (they are the same thing and are purely fiction).
That being said my encounters with "evangelicals" have led me to understand that their literary consumption is very limited. Mostly they don't even read the bible but rather read books written by people that tell their version of the bible. They shun almost all forms of literature. A quick google search of evangelical best sellers will give you their reading list. That is a problem because this exclusive consumption is a diet of nothing more than propaganda in the form of revisionist history, pseudo-science, and far-right nationalist populace politics. As a result, they don't know anything else and what they do know is worthless when it comes to facts and reality.
They actually believe that being an "apologist" is a good thing in the evangelist's point of view. They don't understand that being an "apologist" is nothing more than being a propagandist and a liar.
Universities are called that because they instill a universal education. Universities don't practice isolationism, well, the REAL universities don't. There is value in a universal knowledge. There is NO value in an isolationist education.
Being well read isn't about the number of books that one reads. It is about the diversity and overall consumption of universal knowledge. Religious isolationist read a lot of books that all basically say the same thing. That isn't being well read.