Quoting the site:
This coloring book, which was purported to be from the Black Panthers, had actually been rejected by them when it was brought to them by a man later revealed to have intelligence connections. Not to be troubled by the fact that the Panthers found the coloring book revolting, the FBI added even more offensive illustrations, and mass mailed it across America. It so infuriated the white population that they stopped listening to the legitimate grievances of the black people.
So apparently this is what American intelligence wanted white America to think that the Black Panthers wanted black America to think. If I’ve got that all sorted out.