His point is that HomeScreen web apps (for lack of a better term) are fundamentally exactly as secure as MobileSafari.
Even a technical argument is somewhat hard to fathom, since it should be a trivially simple thing to enable, but given that none of us can see the code it's at least possible.
As far as native apps with embedded UIWebViews, this is a believable technical argument, though it isn't obviously true either. In other words, the political argument isn't significantly less likely than the technical one.
"Web apps that are saved to the home screen do not run within Mobile Safari. They’re effectively saved as discrete apps — thin wrappers around the UIWebView control."
Even a technical argument is somewhat hard to fathom, since it should be a trivially simple thing to enable, but given that none of us can see the code it's at least possible.
As far as native apps with embedded UIWebViews, this is a believable technical argument, though it isn't obviously true either. In other words, the political argument isn't significantly less likely than the technical one.