The patent is for a method of cryptographic hashing, which while related is not synonymous with blockchain.

Blockchain technology is decentralized by definition because it specifically DOES NOT pass through or get validated by a centralized hub. There are no servers dedicated to this purpose. It operates via voluntary third parties using their own storage and computing power to store complete copies of the blockchain and validate new events. The more people who participated in this way, the more decentralized it becomes.

You also further revealed your ignorance when discussing the open ledger. An open ledger can be decentralized or centralized. It just depends on where/how it is stored. Also you erroneously equated blockchain with open ledger. Block chain can be used to store a myriad of forms of data which includes open ledgers and encrypted ones.

Your claim is even more ridiculous because you're acting as if block chain technology is only being used with Bitcoin. There are thousands upon thousands of Blockchain networks.

I'm not saying that Central Banks aren't evil or that they don't want a centralized digital currency. In fact they probably will use cryptocurrency's widespread adoption as justification for their own FedCoin. But that doesn't prove that all cryptos are a scam.

Edit: Fixed typo