Translation:Football and basketball are very popular in America.
Rugby football is a collective name for the family of team sports of rugby union and rugby league, as well as the earlier forms of football from which both games, Association football, Australian rules football, and Gridiron football evolved. Canadian football (Grey Cup still has "Rugby Football" written on it), and to a lesser extent American football were also broadly considered forms of rugby football but are seldom now referred to as such.
A sentence can be false and correct at the same time. If someones believes that rubgy is popular, or wants to lie, and says so, then the sentence is not true, but it is still correct unless you make grammar or ortography mistakes.
When we learn a language we must learn also to say things that are not true, and anyway many Spanish people call "rugby" to "American Football".
More problem for me it's the fact that we learnend football also for the sport that is called that way in Europe. I would propose the course uses "rugby" (or "american football") and "soccer".
People seem to be hung up on the fact that they are different sports.
It doesn't matter. Different things are often referred to by the same word in any language.
Think about how orange the fruit and orange the color are both orange despite being entirely different ideas. Or the word I and the letter I.
VNmese use the same word to name the two sports, the name actually describes the shape of the ball. so you would need to relay on context to know which one is mentioned: one of the sports that is popular in America should technically be football not rugby (and by football, I mean American football not soccer that most of the world would call football).
that being said, both football and rugby are accepted here.