Fixed bars are annoying and should rarely be used. But what's even worse is when the mobile version helpfully removes the content or feature that you'd like to see.
Please just have one site, make it efficient, and be done with it.
> Disabling user-scalable (namely, the ability to double tap to zoom) allows the browser to reduce the click delay. In touch-enable browsers, when the user expects the double tap to zoom, the browser generally waits 300ms before firing the click event, waiting to see if the user will double tap. Disabling user-scalable allows for the Chrome browser to fire the click event immediately, allowing for a better user experience.
I doubt that's why. In this case, as the site doesn't appear to render well at all on mobile in the first place, that meta tag was probably just blindly copy pasted from somewhere else that did have a responsive page.
Why would anybody want to enable zoom in the first place? Properly designed mobile web apps should already have decent sized text and graphics. In addition to the iOS orientation bug you mention, there's also that annoying click delay.
A lot of people at StackExchange seem to recommend zooming though:
I may want to zoom to see an image up close, or just to change text size. Outside apple, phone screens vary widely, and so do text sizes. You can't hope to find one that works on all phones for everyone.
Please just have one site, make it efficient, and be done with it.