My question is related to the concept of social distance. Why is there social distance?

Welcome.

Thank you for the clarification!

How about we understand it in the following way? Culture defines almost every aspect of our lives: how we nourish our families, how we respond to trauma, and how we build our community networks. Cultural boundaries take shape across geographic barriers. These differences also manifest in communities with diverse populations — people of all different backgrounds living in a shared environment. Threats from social and cultural groups against communities of color have historically led to life-threatening and often fatal outcomes that destroy feelings of safety and belonging.