Quick, list every app that's on your phone, the reason why it's installed, and the reason why you trust it!
And then getting defensive about removing it if you're told by an expert you've contacting yourself that <App> is (part of) the cause of your woes.
Not exactly the same scenario as you posited.
Windows (and Linux and macOS and other desktop OSes) offer none of these security features without third party software.
There have been a number of articles recently about iPhone apps phoning home regularly without user knowledge.
iOS is arguably significantly better than the alternatives, but lets not kid ourselves as to how far that trust should go.
Services like Guardian Firewall for iOS[0] wouldn't be in continued active development if the OS or review process was sufficient. Of course, there'll be plenty of snakeoil as time goes on, but at this stage, there's a lot of credibility behind the need for these services.