There are many such people making the false statements that bitcoin is centralized and can be controlled by miners in China, the reason for their claim is because China has around 60% of the total world Bitcoin miners.
I removed the remainder of the quote because it's literally the same exact point. 60% of the miners are within the geographical boundaries of China. This means that the government can potentially seize and control 60% of the network's hashrate.
You only need 51% to be able to have a 51% attack. Bitcoin isn't centralized but the concentration of miners makes it less than ideal.