My personal discovery of historical misconceptions and hidden history

This is an essay I have approached before, having great difficulty grasping the prompt. Here's the prompt:
Stanford students possess an intellectual vitality. Reflect on an idea or experience that has been important to your intellectual development. (250 word limit.)

It came to my disappointment to learn that Columbus did not really discover America, or that Thomas Edison was not the first to invent the light bulb. Even more disturbing was learning about the post-Civil War and the reconstruction of the South. The life of the average African American actually became worse after emancipation, and though there was more to learn in my AP US History class, I finally refused to drink the Kool-Aid.

While learning about the antebellum South, I read Harriet Beecher Stowe's Uncle Tom's Cabin to learn about the treatment of slaves. The interaction between slaves and their owners, as it seemed, was primarily negative and brutal but ultimately subjective to the author's views and intentions. However, when I encountered the book, A Peculiar Institution, by Kenneth Stampp, I was immediately astounded by the "other side" of history. Slavery had many negative consequences, but as I previously learned, interactions among slaves and their owners were, many times, mutually beneficial. Not a single history teacher before that year, or a segment from the History Channel, or previous text I had encountered taught me this.

My disappointment derived from the absence of question and being fed information without checking its validity. My experiences in my history class induced me to surpass common misconceptions, draw upon the bias that exists within secondary information, and view the world with a sense of objectivity. In everything I learn, I have a natural impulse to learn further and to uncover information that is not merely given.

All advise is appreciated. Thanks in advance!

I think this is a great response!

I would change "it came to my disappointment" to "I was disappointed"
and change "or" (in the first sentence) to "and" since you learned both.

Maybe you could add an example where you "learned further" but I don't think that it's really necessary.

Thank you! Any further suggestions?

I love the idea behind this. My only suggestion is that you make the essay more clear at the beginning. I did not really know until I got to the end of the essay what the overrall "so what?" was. Other than that, your style is exceptionally fluid!