Most people feel that blockchain technology is decentralized technology. Since it is considered as a distributed, and even public or digital ledger, that is commonly used for recording transactions through many systems, there is a doubt that it can be considered as a decentralized technology. Also, the records the presents in blockchain technology can't be altered retroactively without doing alterations to any of the subsequent blocks. 
That's right blockchain is a decentralized technology. You're information will be stored by Blocks in public keys. it's very hard to hack.
Wait what? Information will be stored by blocks in public keys.
You know what public keys are, right? Public Keys are used to to verify signatures of bitcoin transactions. Nothing is saved in public keys.
Let me give you the simplest definition of blockchain technology:
Step 1: User creates the data (in case of cryptocurrencies, such data is transaction).
Step 2: User signs the data with his private key and broadcast the data to connected nodes.
Step 3: Miner verifies the data with the public key of user and if data verifies then include such data in block and mine the block.
Step 4: The block containing data is added to blockchain and all nodes update their chain with new block.
Now such addition of data in blocks can be decentralized as well as centralized. So it cannot be said that blockchain technology is always decentralized. Well, I would say that except Bitcoin's blockchain, every other blockchain is in one way or the other centralized or possible to control.
Decentralization is extremely important, but unfortunately the government thinks differently.
Governments don't hate blockchain technology. Government rather hate cryptocurrencies because they assume that their control on financial system will lose due to the use of cryptocurrencies.