We all work from a particular set of life experiences and social locations. Even for empiricists who ostensibly believe in positivism, the personal does find its way into one's research, scholarship, and writing. For my buck, it is better to know such things beforehand as they are a value added that appears between the lines of a given text, offering context, color, and influencing a text's unstated assumptions.
To point, Tim Wise is a friend of WARN. Whenever I get a chance to shill for one of his essays (the newest on Derrick Bell and Obama is great by the way) I do so. He is also a great speaker, one who is generous and patient with his audience and hosts. The above interview offers a narrative for his life's work, views on social justice, and shares some great insights on critical pedagogy.