For those people, To Kill a Mockingbird is very dangerous, because it espouses the MLK philosophy (colour blindness) which most people agree with, but which they hate.
For these modern "anti-racists", we must instead see race everywhere, and factor it into every aspect of our lives, making constant calculations and adjustments which we can never hope to do correctly, and which contain internal contradictions we can never resolve. This hands those people tremendous power.
They are like parasites who have taken over a host. It took massive effort to reach the point in society where almost everyone agreed racism was unacceptable, and legitimately feared being called a racist. Like all "isms", we reached the point where almost everyone stopped thinking about what these terms actually mean, and just started substituting the word for a value judgement: racism bad, anti-racism good. This is the perfect setup for someone with different goals to hijack the concept.