Because they don't have any match going traditions. When there grandparents landed here at the earliest probs 1958 (Sikhs) then Hindus from Uganda 68-71 the grandparents either started working straight away and didn't bother with following football (despite large numbers living in the old working class areas were the football grounds used to be, including my grandad who lived near coventrys old ground highfield road) or just had it as a side thing but nothing to serious. Their kids therefore didn't have any direction from above like the working class white man would from his dad and grandad and granddad before him who would have been going to matches and live in the same area for generations. Hence they just picked the most successful team, which at the time would probably have been Liverpool. As they never go games or follow it religiously but instead encouraged to study and pursue medicine or wahtever else football is put by the wayside and they sort of follow it from the armchair. Hence, their own children just pick a team and role with it. You often find these are the type of people who never go to games and also tend to live as far away as possible from the club. They even miss matches that are on the tv sometimes lol