Alas, I've just Googled this and the real story seems to involve a clash between a militant Buraku organization- which thought the subsidy to the Buraku should be payable only to its own members- and a less militant outfit affiliated to the Communist party.
This is what Wikipedia has to say-
The Buraku Liberation League is considered one of the most militant among burakumin's rights groups. The BLL is known for its fierce "denunciation and explanation sessions", where alleged perpetrators of discriminatory actions or speech are summoned for a public hearing before a panel of activists. Early sessions were marked by occasions of violence and kidnapping, and several BLL activists have been arrested for such acts. The legality of these sessions is still disputed, but to this date authorities have turned a blind eye to them for the most part, except in the more extreme cases.
In 1990, Karel van Wolferen's criticism of the BLL in his much-acclaimed book The Enigma of Japanese Power prompted the BLL to demand the publisher halt publication of the Japanese translation of the book. Van Wolferen condemned this as an international scandal.
The other major buraku activist group is the All Japan Federation of Buraku Liberation Movements, which is affiliated with the Japanese Communist Party (JCP). The Zenkairen often came head-to-head with the BLL, accusing them of chauvinism. The bickering between the two organisations boiled over in 1974 when a clash between teachers belonging to a JCP-affiliated union and BLL activists at a high school in Yoka(rural Hyōgo Prefecture) put 29 in hospital.
In 1988, the BLL formed the International Movement Against All Forms of Discrimination and Racism (IMADR). The BLL sought for the IMADR to be recognized as a United Nations non-governmental organization; but, in 1991, the Zenkairen informed the United Nations about the alleged crimes the BLL had committed. However, when suspected cases of discrimination were uncovered, the Zenkairen often conducted denunciation sessions as fierce as those of the BLL.