I haven´t insulted anybody. It was a joke. This was certainly not an offense against anybody. If you have no arguments against the links I´ve provided, it´s ok. Germany is no more or less responsible for WW1 than any other European major power of 1914. And denial is not a river in Egypt.
Yours: "It´s for 9 graders, but that shouldn´t be a problem for you. ;-) "
Also yours: "I haven´t insulted anybody. It was a joke."
Given the other sentences in your post/s, adding the smiley face doesn't convey "joke."