No, you're wrong. It's entirely decentralized. Have a look at the spec: https://github.com/onenameio/onename

Anyone running a full Namecoin node (ie, anyone running Namecoin client) can register an identification.

OneName is providing a convenient web portal to this key-value store on Namecoin, so their business model is somewhat analogous to Blockchain.info's (or perhaps they have another business model in mind, who knows?).