You're definitely correct that the history of violence and oppression perpetrated by whites makes most highly uncomfortable and I would posit that there is another dimension to this phenomenon also: the economic dimensions of systemic oppression.

Americans are just as wary of discussing the history of black enslavement as they are with talking about the economic benefits garnered from that enslavement.

Once one acknowledges the inherent evil of the commodification of human bodies, it is not a far stretch to recognize the wickedness of exploiting the present-day worker through perilously low wages, precarious jobs and deeply regressive tax systems.

Indeed, MLK realized this early on, and that is why he began the Poor Peoples' Movement.

The danger of deep-diving into the subject of oppression lies in the fact that it may cause too many people, white and black alike, to realize that capitalism is a system that thrives on exploitation of all kinds, something the political establishment cannot abide.