I'm a bit confused. Why would you want that? Shouldn't zooming just make things bigger?
When text reflows while zooming, you can choose exactly the size that is most readable for you.
For example, if I read while walking, I usually make text size larger, because it improves reading speed.
And you can comfortably use desktop versions of websites.
The difference is mainly intelligently limiting DIVs (columns) individually to the available viewport horizontal space. Ctrl-plus and Ctrl-minus does not do this, it tries to fit whole width.
Shame that other mobile browsers have made it their mission to imitate whatever mobile Safari is doing.
It can be an annoying feature, though there are other things that can be annoying about actually reflowing the text as well, as a lot of the mobile layouts are already cramped, and as such zooming could cause other issues.
It's a situation where you're given several really bad options, and you need to pick one you feel is most optimal. Locking the viewport to a specific zoom-level to prevent the side-to-side swiping is an accessibility issue, but makes the layout simpler.
No, it's fine, as long as it reflows individual columns to full screen width. Reflowing whole width (multiple columns side by side) is not useful (like what desktop browsers do) exactly because it'd get too cramped on a mobile device screen.
My biggest issue with iOS it has no usable web browser. Zooming doesn't reflow column text to screen width. IMHO, the single most important feature in a mobile phone web browser.
So now web site authors have started to make these horrendous mobile versions with zoom-locked viewports.
Opera is still the only way to go for mobile phones. Note, not Opera Mini, but Opera.
So far this issue has kept me away from iPhone.