I kinda get the rationale for breaking embargo and disclosing information about a vulnerability to the world. I don't agree with it, but I at least understand why someone might think that's a reasonable thing to do.

I don't at all understand why anyone would try to publicly announce the fact that a vulnerability exists without actually knowing the details. The fact that the exists some vulnerability in a product doesn't give you enough information to protect yourself from it (short of not using the product at all, but that's generally infeasible). But the knowledge that there is a critical vulnerability in a product does give malicious actors reason to dedicate effort towards probing that product to try and rediscover the vulnerability. So announcing this helps nobody and potentially causes great harm.