I has a theory.

The 'Majority' of Sydney FC fans come from 'Western Sydney'. Western Sydney has a lower socio-economic ratio to that of those living in Inner West, North Shore, and Eastern Suburbs. Because of the lower socio-economic lifestyle, the people cannot afford fresh fruit and vegetables to live a healthy lifestyle. Therefore they consume a lot more fast-food then regular people, because it's cheaper then a healthier lifestyle and easier to access. They are therefore more overweight then the rest of Sydney, and therefore less active and more un enthusiastic to catch public transport. Public transport takes longer; however is cheaper then driving. People are too lazy, and too impatiant to catch public transport, and because they're more unfit then your Easterner/Northerner, they're less likely to want to waste energy walking up forveux street.

In short: Western Sydney fans are too fat and lazy and therefore cannot give a fuck.