I see it a bit different: because we want to get rid of oppression, we keep falling for new oppressors. You can see it if you look back in history - the worse conditions get for the people, the easier it is for extremists to get to power. Hitler is a parade example for this. He was not elected for his weird race theories or whatever he came up with later on. He got into power because the previous rulership was incompetent, corrupt and degenrated, and let the masses fall into poverty and despair. Sounds familiar?
Thats why history repeats itself, propably since the first clan chiefs ruled over our cave dwelling ancestors.