Because it didn't have much of an effect on your countries. Not much of a major event in European history.
Wrong actually (although that tends to be forgotten, even here). Where do you think all (or at least a lot) of all that cotton was exported to? And in any case, it all links up into slavery.
And that's no reason not to teach something anyway.
Our basic history courses are very America-centric. Even world history that we do get taught is based upon how it influenced America. I'm jealous of Europeans for getting a broader lesson in history, I barely know anything between the fall of the Roman empire and the discover of the "New World" as far as what I was taught in school is concerned. What I do know is rooted in dabbling and research I've done on my own time. What's more frustrating is the widespread belief that if it didn't influence us then why should it matter to us? Perhaps we'd be less haughty and more cautious in our foreign policy. Sigh.
Really?
Our world history purposely ignored America for the most part. It did tie it in where its influence was large (like the end of WWI or the Pacific war during WWII).. but we started with neolithic cavemen and progressed through Egyptians, Sumerians, Greeks, Romans, the dark ages, Medieval Europe, the Renaissance, and then the Industrial Revolution.
Our world history wasn't Amerocentric, but Euro-centric. We learned almost nothing about the Middle East, Sub-Saharan Africa, or east Asia.