Moreover, people immigrating to US from China tends to be more pro-democracy than average Chinese, but we got disillusioned after seeing how things worked out in American politics.
The life here is quite unsatisfactory for lots of Chinese, as there are many aspects of China making it a better place to live in compared to US. Can't speak for other people but frankly if I could have got a job with similar pay and similar workload in China, I wouldn't even hesitate for a second that I'd move back.
What parts of American politics disillusion you? And why do you think the USA should necessarily be the example? Do the criticisms you have of the USA also apply to other democracies, like the Democratic socialist countries in Europe? If not, why do you think they would constitute an effective argument against Democracy? "The USA has problems" is not an argument against Democracy.