It's more that people believe that to get ahead takes more than hard work - you need to identify as middle class, and display middle class culture. Part of that is denigrating the working class (even if that's where you're from) and thus working class hobbies like rugby league.
Very good point. If you want to 'get ahead' there's only one place to go - up to the middle class. You can't improve your lot and retain your lower class values (you actually can, but the perception is that you can't). All media advertising would have us believe that middle and upper class is the only place to lead a satisfying and constructive life.