How come people of different ethnicity and backgrounds unite for a sporting event and be different o

Good question! But there are many other ways and events in which people from differing backgrounds participate and unite. But sporting events as you say, are probably one of the most common and visual ways for all peoples to come together and be on an 'equal global playing field', without war, racism, poverty or religious tensions. It's a wonder that we can carry on the way we do in this world and then turn around and stage such wonderful events such as the Olympic Games!