No, I don't think that you are stupid, this is why your first question (how does that make it the most popular sport on earth??) seemed strange to me given that you tend to avoid this type of comments and support with arguments any idea you express in the forum. Now, I don't have any data to support my comment referring to soccer as the most popular sport on earth, but I think it is pretty obvious.
The teams there were all european because I was talking about the European Champions League, the equivalent to the Libertadores Cup in South America and others in Asia and Africa.