The Civil rights movement in the US was by and large made of peaceful protests and was rather successful.
How many troops did we have in Germany when we invaded it in WW2, and how many were stationed there after the war in the late 40s. Same answer - you need a lot more troops at the time you invade the country.
We didn't try to police Germany? I think you need to go back and read your history. Today's Hint: U.S. Constabulary
We were in Germany for The Soviets.We were not killing thousands of innocent Germans like we were in Iraq,Afghanistan and Vietnam.