The reason was not exactly animal cruelty. But the fact that it "corrupted the thinking of the working classes."
Zhou Enlai, Prime Minister of China between 1949 and 1976, had the opportunity to express his views on greyhound racing in Macau. He did so "in conversation with a renowned person in the social circles of Macau and Hong Kong", whom he met in Beijing when preparing for a trip abroad, in mid 1965. The conversation was later reported by the Hong Kong newspaper Seng Tou, quoted in Macau by Si Man and translated by the Portuguese weekly Clarim. The Consul of Portugal in Hong Kong at the time, Eduardo Conde, ensured the information reached the government in Lisbon, which at that time already followed with particular interest all that it concerned the Canidrome in Macau (see main text).
According to the newspaper Seng Tou, in a translation published by Clarim, Zhou Enlai "complained bitterly against greyhound racing, because this game corrupts the thinking of the working classes and promotes distancing from their 'educational' meetings which usually take place at the end of each week, according to the best of his knowledge".
"This distance," inferred the Chinese prime minister, was due to the fact that "all of them (members of the working class) stay at home listening transmitter stations that communicate the results of races and their predictions."
It is not known who was the interlocutor for Zhou Enlai, and the reaction of the Macao authorities to the opposition expressed by the head of the Chinese government against the racing of greyhounds. But at the Canidrome nothing would change. Ironically, at the time the head of its management team was Ho Yin, officious representative in Macau of the Chinese government and, as such, frequent interlocutor of Zhou Enlai and Mao Zedong in his working visits to Beijing.
