I don't have the twitters but can imagine it's basically "we can access all the data, the apps, the location, etc..." There is a reason many government agencies ban employees from having it on their phone.
And I feel like I mentioned it here before, but who knows... I have a buddy who has fights with his kid (and wife) often because they want to use it but he bans it since he's connected to the national security space and knows how it can be used by an adversary!
There's been an uptick on China is great material passing through my pages - more in the past few months. They don't have to work too hard to demonstrate their achievements.
