I went through most of the comments on the actual stacker news post, and it seems like the authors fears are majorly solved by nip65. Considering I run my own relay and client, the protocols are equally decentralized to me. I just the requiring all users to run relays is extra overhead. Do I think it's nice that some clients also store your data locally? Yes, but that should be up the the consumer. The user should be free to decide if it's valuable to them to store their notes on their phone or if they trust their relays.
I don't necessarily care about how decentralized a protocol is in early stages, but how decentralized it could be. The benefit of nostr is that the client and the relay is separated, so the user has a choice for both. There is a single client/relay on hole punch for messaging, so until there are more than that, it's not decentralized right?