It seems to me that you (and perhaps DiAngelo was also) raised to be unusually naive about the ongoing nature of racism in the US, and you're now (and perhaps she also) assume that the rest of us were either raised equally naive, and/or our life experiences have allowed us to remain happily naive. I assure you that this is not the case, and you're overgeneralizing. Several points can be made:

1) I would hesitate to guess the % of people who feel uncomfortable (or would feel uncomfortable) having tangible discussions about race, but it is certainly not a universal problem as you assume. I do think its rather human to not wish to offend when discussing a sensitive area, but that concern isn't race-based; people try not to offend in conversations about religion, politics, and breastfeeding as well. I would completely agree that more meaningful conversations about race should occur, but I think you'd be surprised how many people would have no concern in having them.

2) It is strikingly naive to assume that people are surprised when the subjects of institutional racism or informal segregation that still exist in America appear. No person who has ever worked in the schools or in health care, and that is a VERY large cross section of America, (just to name two professions which see this very clearly), are surprised by that. It's not breaking news as you think it is.

3) Labeling a society to be "racist" is a matter of opinion where reasonable people may differ; there is no agreed upon criteria. However, assuming that people raised in that society are racist by mere definition is sheer madness.

4) Ultimately, people are defined by their actions. If the actions you take are nondiscriminatory, and you support rooting out discriminatory actions when they are found, then sleep well at night. You're a good person. :-)

5) The only truly unarguable point you raise, is the last "pillar", which is "internalized superiority and unconscious or otherwise investment in the racial order." Yes, this persists, because it is a passive rather than an active paradigm. As for what to do about it....see (4) above.

One further thought:

“In a racist society, it is not enough to be non-racist, we must be anti-racist” (Angela Davis)

In finding quotable quotes, I would suggest to you that choosing an individual who believed that the only way to be an anti-racist is to be a communist, so the state could re-educate (5) above out of you, is a good choice.