Teachers can't teach what they don't know. Students won't learn what teachers don't teach them.
Back when I used to do teacher training, there was one single piece of advice I always included. Stop assigning pro/con writing assignments in the name of objectivity. Instead, teach your students how to put evidence in context, then come up with a thesis and write the paper.
When you assign something like "Truman's Decision to drop the bomb was correct, blah blah blah write the pros and cons and do research from websites on the internet..." you are teaching them terrible lessons.
First, you are introducing confirmation bias by assuming that there was a "decision to drop the bomb." Then you are teaching them to become advocates for that bias instead of the truth. Then, when you swoop in and say that "the answer isn't black and white, but rather shades of gray" or the "truth is somewhere in the middle" you are implying something false. Maybe the truth is there somewhere. But it doesn't actually have to be in the middle between two false assumptions. Maybe the truth isn't gray, black, or white. Maybe it's purple. Or Jabba the Hut. But by introducing bias at the beginning we might never know. And there are many true narratives that can all exist without being exclusive to one another. You can understand that the dropping of the atomic bomb saved lives and still be against it. (Side note: If the truth challenges your values, maybe you should re-assess your values? Do you really want your beliefs to be based on lies?)
I sometimes say that my classes are about learning the box, not thinking outside of it. Tell me the true story of what is in these good, legitimate sources that I, as your teacher, have put into context for you. That's hard enough. You have to do that for years before you would even know where the box is. Then you get to think outside of it.
Pro/con lists may play a valuable role in your life, but they have nothing to do with a search for truth. And if you are training to be a lawyer, by all means, learn to be an advocate by arranging facts to fit a predetermined thesis. But leave that to the law schools or some other institution that teaches people to be effective liars or propagandists.
Stop thinking that we need to balance bad sources with good sources and that the truth is somewhere in the middle between extremes. The Holocaust happened. It's true. Lincoln once said of slavery that if slavery isn't wrong, then nothing is wrong. Let us now say about truth that if the Holocaust isn't a fact then nothing is a fact. If it didn't happen then nothing has happened. If it wasn't wrong, then nothing is wrong.
Parents, if your school isn't teaching your child that the Holocaust happened, and that it was the ultimate expression of concentrated evil in all of human history, then you need to do it. Today.
(Note that I said "concentrated evil." Obviously Communism killed more people--around 100 million people and counting, making it the deadliest and worst idea overall-- but did so over a much longer time period).