Testimonial
As a graduate student in the humanities, I have witnessed firsthand how the political biases of university faculty often get in the way of the education these people are paid to provide. While most professors truly care about their students and the free expression of ideas, some individuals feel their position exists solely to provide them with a podium from which to preach their ideas. To be fair, this is true for both liberals and conservatives, but the overwhelming majority of university professors lean to the left, making the 'liberal bias' even more pronounced in academe.
Let me be the first to admit that, though I am in many ways liberal in my political beliefs, I have often decided to keep my mouth shut in class, or while writing a research project, in order to protect myself from receiving lower marks than I deserve because an idea I have might raise Republican red flags in an environment unwelcoming to alternative viewpoints. As an undergraduate you learn very quickly how to distinguish between the (majority of) professors who will allow you to differ from them, if you can support your opinion with solid research and thoughtful analysis, and the professors who will grade you based (at least partially) on your politics.
It is a sad fact of life that it is necessary for a student to make this distinction between the fair-minded professors and the ideologues, but if you want to succeed in academia, you need to learn when it is 'okay' to speak your mind and when you are better off pretending to conform. I guess you could say that makes me something of an intellectual prostitute, selling my political silence in return for a quality education, but maybe when more people like myself are in positions of power, we can put an end to this necessity; the Thought Police will be retired in shame.
As a final note, I did not attend Berkeley, or any other school notorious for its leftist leanings. I attended a large public university in a red state in the Midwest. The vast majority of my professors (whether they were open to new ideas or not) were card carrying Democrats. I am sure you will find my experiences are not unique.