I live under the philosophy that anyone can learn something from anyone, no matter how intelligent or not, or how good or not the other may be. If you choose to listen only to people who agree with your philosophy, you learn nothing.
In law school we are taught to learn both sides of an argument. If you know the strengths and the weaknesses of both sides of an argument, you are in a better position to argue your side of the argument.
Too many people choose what they will believe and not believe and then close their minds to all arguments that differ with their chosen beliefs. These people are defiant to cogent arguments that may reveal flaws in their belief system.
I have read books written by lawyers, philosophers, physicists ... Hitler, American Indians ... biographies about Dr. King, Gandhi, Jefferson, Franklin ... philosophies about Christianity, Judaism, Marxism, Capitalism, Atheism ... history as told by Americans, Indians, Chinese, French ... to name a few. The idea is to understand why different philosophies develop. Why different people think differently. You can choose for yourself if your philosophy stands "as is" or needs revision or falls to another philosophy. But how can you truly know you are on the right track if you only listen to yourself and others who think like you.
And if you fear exposure to "unnecessary evils," then you must question your own beliefs. Because if you fear words that different from your own, you must have doubts in your own beliefs. And if you have doubts in your own beliefs, then you must ask yourself if you are wrong. And if you are wrong, should not you discover what is right?