Angola liberated itself from Portugal in 1975--as part of a worldwide trend against colonialism.
The leader of the "Soviet Union" at the time, in the tradition of all neo-colonialists, L. Brezhnev sought to take advantage of the tight spot of the Angolan people in fighting Portuguese colonialism. Rather than see fighting colonialism as a matter of principle, Brezhnev excelled in dividing anti-colonial forces by aiding only those who agreed with him. He did this so well, that many calling themselves "communist" interpret what happened in Angola only in the light of things appropriate to a country that has already de-colonized. They talk about Angola not as if it were liberating itself from colonialism but as if a socialist country were in combat with U.$. troops.
In contrast, Mao in China stuck to first things first in accordance with the stage of the struggle and he aided all organizations in Africa seeking aid against colonialism, as a matter of principle. As a result, despite disagreements with Mao, Che noticed in Africa every where he went that Chinese weapons and money were to be found. According to Che, the Africans had even received too much aid and were sometimes better equipped than the colonialists.
China was no where near as well-off as the "Soviet Union," but Chinese help to the anti-colonial struggle was everywhere. The Brezhnev revisionists influential to this day in polluting the political work of people such as Ludo Martens and the followers of Hoxha took advantage of the situation to say that Mao's aid went to groups that other Western imperialists were also aiding! This cheap shot worked, because Mao aided all anti-colonial organizations who asked for aid. As witness Dennis Brutus said in referring to the ANC, the Chinese told him they will give aid to their struggle against apartheid, but they have to ask. The neo-colonialist revisionists in the pro-Soviet bloc are so used to choosing countries' leaders for them, that they cannot understand the principle behind aiding all who ask for help against colonialism!
Peking Review: Official voice of the People's Republic of China under Mao
Maoist government hails joint communique of three Angolan organizations
Maoist government hails liberation of Angola from Portugal