I don't think it was made by China but there is a concern regarding China. According to many sources, over 51% of BTC's hashrate comes from China. If their authoritarian government decided to ban it, at the very least it would crash the price and potentially threaten the security of the network. But if they could figure out a way to use that hashing power to destabilize bitcoin...I don't know, it's just concerning to me and why I don't hold any bitcoin, even if I think it will do well in the next few years.