> The takeaway is that for all intents and purposes, anything you did in a private session or secondary profile on an Android device with any Meta app installed, was fully connected to your identity
Definitely, and that's a huge problem. I just don't think Android business profiles are a particular concern here; leaking app state to random websites in any profile is the problem.
Or do Android "business profiles" also include browser sessions? Then this would be indeed a cross-compartment leak. I'm not too familiar with Android's compartment model; iOS unfortunately doesn't offer sandboxing between environments that way.