Not that selection, but the process of evolving theology. It's very simple, really, and has been going on since Eden. Anyone can do it. In fact, almost everybody does do it.
First you choose a doctrine. Then as you study, or more likely, just run into things, like sermons and opinions, you collect the things that agree with your doctrine and throw out the ones that do not. Soon you will have a custom tailored, form-fitting theology of your very own. Then you can square your shoulders, look the world in the eye, and proudly declare, "I agree with everything I believe in."
This tried and true technique avoids the trauma of ever being wrong. Your ego remains intact. In fact it gets bigger and bigger with the passage of time.
"But what if I don't have a starting theology to build on?" you may say. Not to worry! You are born with a set of beliefs that are just fine. Plus, the Father of Lies will give you a set if you are still unsure. It worked with Adam and Eve. It worked with their son Cain too.
So you see, we all have a kind of "sourdough starter" theology to build on. We can give some of it to neighbors and friends, and soon they'll have plenty of it too. And this is just the beginning! You may have a desire to associate with those with similar theologies. These associations are called "denominations". They can be as varied as you want. So-called "sexual orientation" is no bar, and atheists can have theirs, too.
Building upon inborn and Satan-acquired prejudices works. Humanity and its history have proven that. You will find comfort and ease in this course of action. You will fit in. And, perhaps best of all you will not have to think, and nobody wants to do that.
Are there any who do not follow this natural process? Only a few. Poor, isolated souls they are too. Some follow and study the Bible alone, as if that was important! They claim that they commune with Christ, and that He has even promised to sup with them. Some believe that online evidence proves that their numbers are growing. Pay no attention to them. May their immortal souls "rot in hell", whatever that means.