"The first thing people say when a mass shooting is announced," Rock wrote in the caption. The unspoken punchline: Bet he white.

Some white critics called Rock a racist. But the comedian's defenders invoked an old argument: He can't be racist because he's black. While others can debate whether Rock is a racist or not, the reaction to his meme raises a bigger question:

Why can't blacks be racist?

There's a popular belief that people of color can't be racist because they don't have enough power. Racism, the thinking goes, transcends prejudice. It's a system of advantage based on race and people of color don't have the institutional power to oppress others.

But Ibram X. Kendi systematically demolishes this notion in his provocative new book, "How to be an Antiracist." Kendi, a lean man with long dreads and an encyclopedic knowledge of Western history, says the notion that black people can't be racist is tainted by racism itself.

"Like every other racist idea, the powerless defense underestimates black people and overestimates white people," Kendi says.

Kendi's new book is essential reading for anyone trying to figure out why racism remains such a destructive force in American life. There is arguably no better commentator on race in America today. Kendi's previous book, "Stamped from the Beginning," won a National Book Award. He is also the founding director of The Antiracist Research and Policy Center at American University and a 2019 Guggenheim fellow.

Ibram X. Kendi's latest book was published last month.

In his new book Kendi explains why there is no middle ground between being a racist and someone who says "I'm not a racist," why Americans are trained to see deficiencies in people instead of policy and why he fears a second term of President Trump.

CNN talked with Kendi about the book. This interview has been edited for clarity and brevity.

You say in your book that no one can claim to 'not be racist' because there is no middle ground between being a racist or an anti-racist. What did you mean?

I think people will understand the people who are actively supporting racist policies. I think people will (also) understand people who are actively supporting anti-racist policies, and how they are anti-racist. But what about the people who are literally doing nothing? The status quo -- what is mainstream -- is racial inequity. So to literally do nothing in the face of the status quo of racial inequity is to essentially support the status quo. It's just like, for instance, what slaveholders wanted people in the North to do in the face of slavery, which was nothing.

You also say that hating white people becomes, in the end, hating black people. How does that work?

You have white people who are in positions of power to shape policies, and then you have everyday white people. Who should we focus on? Should we see those people in positions of power as pretty much the same as ordinary white people? I'm saying, no we should not. Specifically those whites who are in positions of power, who are using that power to defend or institute racist policies, they are the source of this race problem.

For us to focus our efforts on any white person who says something or does something that's racist as opposed to those in positions of power -- whenever we take the focus off of those people in positions of power, we are taking the focus off of the source of the problem. By taking our focus off of the source of the problem we're allowing that problem to fester. And by allowing that problem to fester we're making the lives of black people worse. That's how hating white people becomes ultimately hating black people.

Why do you think black people can be racist as well? You've heard of the argument that people of color can't be racist because they don't have institutional power.

So generally white people say, I'm not racist, and black people say, I can't be racist. There's a similar form of denial that is essential to the life of racism itself. You have black people who believe that they can't be racist because they believe that black people don't have power and that's blatantly not true. Every single person on earth has the power to resist racist policies and power.

We need to recognize that there are black people who resist it, and there are some who do not because of their own anti-black racism. And then you have black people, a limited number, who are in policy-making positions and use those policy-making decisions to institute or defend policies that harm black people. If those people were white we would be calling them what they are -- racists. If they're black, they're no different. They're racists.

What happens if President Trump is re-elected?

His policies will have an even more damaging effect on so many communities, the way in which his racist ideas are dividing and conquering Americans. That will only grow deeper. White domestic supremacist terrorists -- they will continue to rise and harm Americans, specifically because the President is not willing to view them as as a domestic terrorist threat. And ultimately I think he will try to run again in 2024. He will try to figure out a way to operate as a king.

Do you ever sense that cynicism and apathy are some of the biggest enemies for any anti-racist work?

Yes. Cynicism is the kryptonite of change.

One of the big surprises for me came near the end of the book when you said we could transform society so that it can become anti-racist. Do you really believe racism can be vanquished? Where does your optimism come from?

Yes. The reason why I believe that is first based on my reading of history. In 1860, if you had talked about eliminating chattel slavery, people would have said that was completely impossible. Slaveholders are extremely powerful. They're the richest people in the world. In 1790, if we were having a conversation about Haiti becoming a free black republic by 1804, people would have said that's impossible. Haiti is the most profitable colony in the world. There's no way the French or any European power would allow Haiti to be lost to freedom. If someone said that someone named Barack Hussein Obama would become President of the United States, people would have said that's impossible.