You are correct that democracies tend not to help other countries become democracies but instead install dictators so as to exploit them (the liberal interventionalists are wrong)

But this does not mean that democracy doesn't exist.

What doesn't exist? Communism that is no more. China is not communist but nationalist. Communism is nowhere to be found, anywhere.

Democracy is a system for the diffusion of power. It addresses a weakness in human nature 'power tends to corrupt'. You can argue that the chaotic nature of democracies is a heavy price to pay to address this issue.

But it turns out to be the correct thing to do.

The communists did not address this issue and monsters stepped into the resulting power vacuum.