From the Mao link on that page:

Apart from all these, there is the fairly large lumpen-proletariat, made up of peasants who have lost their land and handicraftsmen who cannot get work. They lead the most precarious existence of all. In every part of the country they have their secret societies, which were originally their mutual-aid organizations for political and economic struggle, for instance, the Triad Society in Fukien and Kwangtung, the Society of Brothers in Hunan, Hupeh, Kweichow and Szechuan, the Big Sword Society in Anhwei, Honan and Shantung, the Rational Life Society in Chihli and the three northeastern provinces, and the Green Band in Shanghai and elsewhere. One of China's difficult problems is how to handle these people. Brave fighters but apt to be destructive, they can become a revolutionary force if given proper guidance.

This is more optimistic about their revolutionary potential than Marx, but it still has significant reservations ("but apt to be destructive"). A footnote from the editor adds:

Through these organizations the lumpen-proletarians sought to help each other socially and economically, and sometimes fought the bureaucrats and landlords who oppressed them. Of course, such backward organizations could not provide a way out for the peasants and handicraftsmen. Furthermore, they could easily be controlled and utilized by the landlords and local tyrants and, because of this and of their blind destructiveness, come turned into reactionary forces. In his counter-revolutionary coup d'etat of 1927 Chiang Kai-shek made use of them to disrupt the unity of the labouring people and destroy the revolution.