From what I understand, the ban is on X operating there as a company, not necessarily people circumventing blocks on IP and using it anyway. They can't just tell Nostr not to let Brazilians use the protocol.
Discussion
My understanding is that that here an efty daily fine for those who use a VPN to circumvent the ban on X. Something along the line of 8000$ a day or whatever. I am not Brazilian, but this is what I've been reading, so I am not sure on the values. But if correct is a huge fucking number to pay those fuckera daily, of caught.