So as an Aussie I get asked by Americans, "Where isn't there something trying to kill you?" I turn around, look them in the eye, and tell them "school."
That's awful. Why would you joke about gun violence like that?
Just to piss them off.
While I can understand getting annoyed at being asked stereotypical questions about Australia, school shootings are tragic events in the United States and it isn't considered acceptable to use them to shut down a conversation since it trivializes what happened. Instead of trying to deliberately anger other people, try being more positive when talking with foreigners. You not only would you feel better but I would think that you would be able to start a few new interesting friendships.
I don't care about making friends. In fact I would like to make my own shirts with politics on them like "Trump is the greatest".
That seems like you just want to cause problems. First by making light of something that causes so much pain to many people, like school shootings. Then by making light of our politics.