Even in elementary schools children are taught 'thinking skills.' There is so much more information to learn than when I was in elementary school--even the table of the elements has grown by about 20 or 30. And so, instead of rote memorization (of Bible verses, for example) people are taught how to find, evaluate, and interpret information. This is called higher level thinking skills. They learn to collaborate, to work as teams, to brainstorm, to use their creativity.
People aren't "indoctrinated" at college. They are challenged. If they are liberal, it is because students go there at a time in their lives, predominantly, where they are using those thinking skills to question.
When they try to evaluate and interpret if they are hit with authoritarian roadblocks they will balk or reject them. At some point they will hopefully assimilate faith and values---but not in a pre-digested form.
Meaning no disrespect, I once asked a fundamentalist minister what they studied when they got their divinity doctorates (if they did). If the truths of the Bible are as plain as the fonts on the page--no thought required--then how in the world can you spend years studying them? I guess that there are things like homiletics--learning how to give authoritarian sermons and what not. An Assembly of God minister learned Greek so he could read Bible tracts in their original language. (I hope he did something fun with it, too, like tour the Greek islands).
Learning is about assimilating the facts you receive and using them in your real life. It's the same in politics. I listen to Trump and think, "He's arrogant. He's self-involved. He's inarticulate. He's mean and nasty. He's unlikeable. Is there any truth at all to what he says?" I don't think, "He's an authority figure so I have to believe him." I process what he says and check it against other sources and my own life experience. That is how you should deal with authority figures, especially those who are as blatantly wanting as Trump.