Oh, because it's all about economics and power.
Interesting thesis. At the same time, China has few allies. Does that mean China has a poor economy and little power?
Maybe it's news to you but China has been poor for nearly 150+ years. In the past, China had the highest GDP in the world. But the opium trade, western wars, caused it to become as poor as it did. It's only in the last 10 years or so that China's economy has been big enough to garner more allies.
Even so, maybe propaganda has convinced you that China has no allies? For example, 37 countries signed a letter supporting China's anti-domestic terrorism tactics in Xinjiang.
Part of that is that the last imperial dynasty to rule China was not Chinese, but ethnically Manchurian. A lot of problems came from that. Granted, that does not make it okay that the West helped carve them up. But a lot of their external issues in the past few centuries have internal root.
If the Han and the Manchurians could not get along, how is that the West's fault?
WRT "terrorism" in Xinjiang: I think non-Han minorities might have a different opinion than the official Beijing line.
So China does have a friend in the US. But Xi doesn't.