Trading is of a mutual benefit. Sea creatures do this as well with hygiene.

In case it wasn't obvious, Western influence (individualism and democracy) is an existential threat to the CCP -- This is why see western media censored and/or outright banned in China. Tiananmen Square Massacre is another example of CCP's response to western influence in China.

These days, conflating being each other's #1 trading partners with being allies sounds like Chinese propaganda.

Trading partners is not the same as "literally allies". Germany was trading partners with the rest of Europe before both world wars, that doesn't mean Germany was allied with France and the UK. There is no mutual defense pact between America and China, nor will there be in any foreseeable future. America and China are not allies.