Saying a 13 week power down is a "prison" is like calling a business contract a prison. People can't say they are being forced when they knew the terms to an agreement before hand and then agreed to participate.

You're on Steem, which means that you are a willing participant. No one is forcing you to be here, and no one is forcing you to write or curate on Steem. So, you have consented to the 13 week staking system because you decided you wanted to participate in the game mechanics of Steem.