It's not an issue with the protocol nostr at all! I'm convinced we will build what we need on nostr.
"Social media" is a term for a very broad range of products, including tiktok, instagram and reddit. I just see those clients on a scale with regards on how much they focus on the author and the most successful clients on nostr so far were ones that totally focus on the author and not the message.
Relay-based topic filtering in my opinion is against the spirit of nostr. By locking a topic into one relay you make it more censorable. Of course you could have multiple cigar relays but for me, relays are the ether through which we deliver our notes to the world broadcast-style and the recipient should then decide if he wants to receive my events or not.
