Earlier quoted context omitted.
This is normal pragmatism and real-politik. Mao is looking after his and China's interests. The public are usually fed simplistic, emotional propaganda by their governments, all of them: good vs evil, right thing to do, freedom, whatever. But in fact policies are based on interests and cold calculations.
Funny thing is that things started to go bad for Mao when he suddenly started to have ideals. Luckily Xiaoping entered the chat and the rest is Chinese history. (I have always liked the Chinese for their pragmatism. Americans are too far up their own ass).
I think Deng Xiaoping is a direct result of these developments during the Mao years.
Things would have been very different for China, without the rapprochement with the west. Without friendly terms with the west they would have to maintain an enormously big army.
Think of a China today that is more like North Korea.