The US locks up more people, but not for wrong-think. Instead our country does it for consuming the wrong plants at the wrong time, because our systems are still racist in various ways, and because we have somehow allowed prison to become a for-profit institution.
Those are different problems and they need to be addressed. The war on drugs must end, policing culture and policies must be corrected, the US prison system must be corrected. Other options for dealing more effectively with various social and mental health problems must be instituted.
And none of that is the same as what China is doing to their people, nor does it absolve China of the wrongs it has committed. And it doesn't take the edge off of it either. Going to China can still get you locked up for reasons you don't understand because you said the wrong thing one time and forgot you even said it.
That actually is a more risky situation for most people than making sure they are not buying or carrying around the wrong plants. That is what comments such as the one you are responding to are actually worried about. It's not a raw numbers game for the individual, it's a question of "how easy is it for me or people I know to go to jail for what should be trivial actions?"