I'm sorry but I still really don't get it. Perhaps I'm blinded by "my inner racist" or something, but this comment (from the article comments section) was most relatable to me:

As someone who is sympathetic to the struggles and conditions that many people, not just Black people, live with, I don't find this kind of "letter" to be particularly helpful, for several reasons.

First of all, it seems hypocritical to address all "White Americans" as if we all had the same attitudes, latent or expressed. Imagine the response, should someone write a letter titled "Dear Black America" and pointing out certain failings. People would say: Black people have different experiences, different attitudes, we aren't one homogenous group. And they would be right.

Secondly, and related, if people are really looking to change the world, it is far more effective to focus directly on problematic attitudes and behaviors themselves, rather than attributing them to some group and saying that the group must change. Every person, regardless of race, gender, or whatever other classification you want to choose, needs to look at themselves and see what about themselves needs improvement. We all need improvement because none of us is a perfect, but not because we're White or male.

It's simply not effective to make people feel that they are "wrong" in some way because of their classification, regardless of how prevalent certain attitudes might be within that group. The focus needs to be on the attitude or behavior itself.

and this:

I understand the concept of white privilege, and I understand how I benefit from the community actions, the set of assumptions made about me simply because I am an educated white person of the middle class. I fully understand how it is my responsibility to effect change, and that we are all under the onus of our own preconceptions. But responsibility is not guilt, and being white is not being racist.

I am a racist if my thoughts and actions make so, and only if my thoughts and actions make me so.