If you can identify a person in a country where WA shouldn't be available by sniffing out their profile, it may even end up being a deadly security vulnerability, but I don't blame someone on a tech bro forum for making a edgy comment, it's all in the game.

The most interesting vulnerability is the reuse of cryptographic keys, some of it apparently by design, like when transferring one's account to a new number - this can apparently be used to correlate identities despite the change of phone number.

Also, from examining the published data set I found it interesting that there are only five WhatsApp users registered in North Korea. I wonder who they are.