UIWebView runs in-process. There's no way for "part of" a process to be able to map executable pages without other parts able to, so either they let any app run

UIWebView runs in-process. There's no way for "part of" a process to be able to map executable pages without other parts able to, so either they let any app run whatever code it wants, disable Nitro, or rewrite large chunks of the UI to move WebKit out-of-process.