> I think that is a very charitable assumption about the GP claim. The linked article describes a very specific implementation vulnerability around handling of offline messages that would appear to be routed in user experience being ranked higher than operational security by WhatsApp (understandably).

Both points (security vulnerability and user experience prioritization) can be true simultaneously. This is the root of all plausible deniability when it comes to installing vulnerabilities in technologies.

I don't see why we should care at all about WhatsApp's intentions with the change when the effects are so pernicious. Facebook et al. definitely do not deserve the benefit of our doubt anymore.