The issue here is very simple; the author sees the tactics as self defeating because he doesn't agree with them, or because they don't want to accomplish his own aims - because they challenge the liberal orthodoxy, which he defends by mentioning several policies. To him, only policies can be challenged, and anything other than a policy doesn't count for institutional racism at all. The only exceptions he's willing to make are when racism is so bad that liberal approaches don't work so well - in Dr. King's instance. But I would contend that racism (and indeed sexism and classism) manifests itself in a much more overt and discreet way, but this only makes them categorically worse, just as the workplace example I used.
I'm not entirely convinced he does understand what they want to do, having opted to go for a standard "they just want to control what we think" line rather than addressing their issues with the process as it actually stands. It's a bizarre article which hasn't looked into the history of the movement as it exists, and what its strengths and shortcomings are.