If they didn't mean blockchain they could have not used a phrase that is very strongly associated with it, and instead used any number of other terms in colloquial use that match the properties of the organization they're setting up.

If you look at the sponsors at the bottom of the page linked, the first name is a blockchain company/organisation, which in my mind lends credibility to the fears that they really do mean blockchain and aren't just jumping on the buzz-phrase bandwagon.

We have the words "corporation" or "company" (or "foundation" or "conservancy") for easy to find synonyms of "organization" and despite appearances none of those words directly implies either "centralized" or "decentralized". There are companies and foundations that are built quite decentralized meeting only remotely over the internet today.

Companies and corporations are far from "autonomous" however, and that word currently always implies "smart contracts" and blockchain.