Why should Science Fiction not be referred to as a genre?

Works of Science Fiction cannot be grouped into a singular genre because it does not address the many hybrid versions.  Science Fiction is a global phenomenon that is constantly changing and evolving as technology does. Science Fiction encompasses the genre's of science, romance, and prophecy, however cannot be categorized as one. Science Fiction covers a wide array of media, from books and stories to movies and television. Viewing Science Fiction as a category in which different genre's combine and intersect, better conveys the eclectic mix of pieces of work that fall under Science Fictions category. In "A Very Short Introduction",  Seed looks at the emergence of Science Fiction and examines the way in which technology has affected the human's perception of the world. "A very Short Introduction" shows the different genres and themes within the overarching category of Science Fiction, such as the concept of aliens, the  role of technology in relationship to time and the ideas of utopias and dystopias. 

http://www.rottentomatoes.com/top/bestofrt/top_100_science_fiction__fantasy_movies/?category=14

http://www.infoworld.com/article/2606741/computer-hardware/146149-Science-vs.-fiction-15-sci-fi-technologies-that-are-almost-here.html