Everyone touts that bitcoin is this awesome decentralized currency
No, no it is not. It is very much centralized in China. Mining is cheaper there and 58% of the mining is done in China.
When bitcoin is thought to be decentralised, it does not mean as per mining alone. Its talks about the exchange, the control, the security and even the compulsion on how to go about it and bitcoin surpasses all other forms of fiat that might even come close to comparison.
On the issue of mining, a country has 58% of mining, that's quite high though but does that stop other people from other countries from having their farms? obviously no. That's where decentralisation comes in. If I have the capital I can set up a mining farm, and get bitcoin just like someone in China. Also, for the fact that they are in China based on your statistics does not mean they agree or they decide what happen they are free to choose and that is the essence of decentralisation.