There’s no flaw. It’s not censorship-free. It’s censorship-resistant meaning that you are able to continue to post where people want to listen. No one is going to ban you from the internet or physically come restrain you (unless they’re an oppressive government, for example). In the same way that you’re not going to hold my ears open so that someone can shout garbage into them.
Discussion
I think there is a pretty common misconception of the term censorship though, as somehow it changed from “suppression of speech” to “denial of validation”.
Suppression requires a natural power imbalance between speaker and censor, one that technical systems like Nostr, open source electronic relays, already inherently lack. A relay operator choosing which notes to transmit exercises their right to free speech, they suppress no one, they censor no one.
when you close your ears or eyes you are censoring the information to reach you. maybe you don't want it, that's OK. but that's not "not censorship" it IS censorship. calling it different names doesn't change this fact. nostr is not censorship resistant
take bitcoin node for example. you can broadcast a transaction from your node and I have to see it on my node. I can't ignore your transaction just because I don't like it. that's censorship resistant. not this