Of course they did. It wasn't always open warfare nor does it have to be. The simple fact that the United States and her allies had a large capable military fixed a line on the map that held for 50 years until the Soviet block self-destructed. As for Mao, I'm pretty sure that having the US as a buddy kept Taiwan free as well as secured South Korea and provided a lot of security to Japan and the Philippines. The UK did the same for Hong Kong.

It's not correct to say that we have to attack a country/dictator in order to stand up to them.