Why do socially marginalized groups tend to have a stronger understanding of, and are often more able to use, the sociological perspective?

Because they are more likely to experience it themselves

People that belong in the majority will be less likely to experience subtle injustice that happen in society. To the point where some of them even see the injustice as something that is common and should happen. Because of this, socially marginalized group tend to understand and use sociological perspective with stronger understanding.

an important point to remember about correlation is that while there is a _statistical_ relationship correlation does not equal _causation_

the first answer is: statistical

the second answer is: causation