Fear and Walls

When I was a kid in school the teacher told us about the great wall of china, the lesson was about isolationism. She said what they built it to protect themselves, later on came to hurt them. It was constructed to protect them from the mongols and the mongols were the terrorists of the day.
She didn’t actually say terrorist that’s the connection I’ve made. They the Chinese however were terrorized The mongol raiding party’s would ride in take whatever they wanted and ride out.
She went on to explain it seemed like a good thing at the time to build a wall to keep them out, No one realized that if you built something to keep the bad out it would also keep the good out.
She said as time went on progress pasted them by.

Then later when I was high school we learned about the Berlin wall. Again were told that it was stupid to try to keep what you perceived as bad out and good in. That it would always come to keeping good out as well. and then after high school On June 12, 1987, President Ronald Reagan gave his "tear down that wall"speech and down came the wall.

OK lets flash forward to today we have a wall a big ass useless wall across the border between America and Mexico. what next the great Canadian/American wall across the northern border.
How did we get here?
What in the hell happened to us?
Does any remember F.D.R.'s “The Only Thing We Have to Fear IsFear Itself” Speech?
Was this stupid dyslexic kid the only one paying attention in class that day?
Doesn’t anyone else see the similarity in whats happening today?
We are destined to repeat our mistakes if we don’t remember our history.
Do we really want someone standing out side our borders in front of our wall giving us a hey you guys are stupid "tear down that wall" speech? cmon aren’t we smarter than that.
I sure as hell thought so but I guess after my education post I shouldn’t expect too much.