The article doesn’t state that at all actually. It just says, according to SpeedTest, China has deployed more of the spectrum already where as the US is only rolling out mid-band frequencies (as of 15 months ago). It says nothing about China having special frequencies not available to the US, nor does it (incorrectly) state that Huawei invented 5G.
You’re probably not familiar with the landscape of the US, but much of the country is rural which is why we have more users per tower since it isn’t financially advantageous for companies to roll out new towers where few people can use them.