Amongst other things the theme of land theft and the way Native Americans are portrayed. The damn buffalo aren't just "Native" like they are native stereotypes. Worse yet the episodes paints the conflict as equally the buffaloes fault when the settlers moreor less take land that isn't theirs, futher more they don't need it. They can always go back to Canterlot, Ponyville etc. It's not the worst thing in the world but man this episode was rough,
I think you're looking WAY too deep into a children show about talking ponies. I liked this episode because it teaches a lesson that's very important in real life: Learn to communicate peacefully with others that cause a conflict for you. Something that our governments don't seem to realize...I think. I don't know, I don't pay attention to what the U.S is doing to try and get attention.