The liberal establishment realized that as long as blacks were talking about blackness, as long as blacks were cussing white folks, as long as blacks were only reclaiming themselves, they were not the threat which they could be. A threat did not exist until blacks moved from blackness to an understanding of White Power (the system) and organized to destroy it. Suddenly the Establishment began seeing virtue in blackness and began encouraging it, as did even funding groups, whose programs were essentially cultural. Too many blacks thought that having won the right to assert their blackness meant more than it actually did. Blackness became an end to be achieved, when in actuality blackness is only the starting point. It is one weapon in the liberation struggle. For too many blacks it has become the struggle itself.
Lester's insider theory (at least in this chapter) is that by the late 60's Black Power had already lost its way and was being actively encouraged toward a direction less dangerous to the established powers. To me at least, the effects sound parallel to what Lloyd describes here.
I couldn't find the chapter online as a standalone, but a scan of the book is available for free checkout if you sign up at Archive.org: https://archive.org/details/revolutionarynot00lest. It's a short chapter, and is on pages 104 to 108. It's a fun quick read even if getting to it is not trivial.