@David09 - Frankly, I don’t think bias is the main problem in the student papers I read when I was a teacher. It’s precisely the lack of facts that is the problem.
I found that students would make compelling theses statements but fail to back them up with solid facts that supported their arguments. In some cases, the facts they did choose seemed to reinforce the opposite conclusions than what they were writing about!
I saw more fluff and a lot less meat in the papers that I graded. I think it’s not so much bias that is at issue, but that we have become very opinionated, and students don’t dig deep enough to support their arguments, resting on mere assertions alone to carry them through the paper.