No, there are few to no actual privacy improvements over centralized systems.
Perhaps even functional regression: what, are you going to run a hash blocklist across all nodes? Like spamhaus? Is there logging or user accounting? Is anything chain of custody admissable, or are we actually talking about privacy and liberty here?
Is everything just marked, "not for unlimited distribution"? And we dwpend upon there not being bad actors?
Real costs are very different with just friendly early adopters.
Cryptographically signing posts (with LD-Signatures) may help with integrity, but that can be done with centralized systems and does nothing to help with confidentiality.
What about availability?
Is it a trivially-DOS'able system?