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. But if you check about this indept, you will be able to know that bitcoin is not controlled by China.

Who are the people buying Bitcoin? Are they from China?
Most Bitcoin are mined in China is compared to individual countries, around 40% of bitcoin is not mined in China, most Bitcoin mined in China are bought but people from another country. So, Bitcoin is mostly mined in China, but not all is mined in China, while most of the Bitcoin mined in China are bought by people and institutions from another country. Some Chinese miners are even move to Siberia to mine while things can happen in the future to let some country you do not expect to evolve to mine Bitcoin.