This is a great example of why mobile browsers suck. It is the job of the mobile browser to be able to fix these problems automatically, to resize and reflow text so that it displays properly on the device.
As a developer, you should define which content should scale and/or resize according to browser viewport width and pixel density: Better known as "Responsive".
Mobile browser should render the page exactly how the designer specified.
And: It pisses me off to no end that Google is in the position to decide how a site has to look like on $device.
They announce that you will get a worse SERP if your site doesn't do X and everyone scrambles to please mighty G.
If they decide that every site has to have a yellow background, starting next week, what will you do? Give in?
However, if they are right, and the users _do_ want to see sites optimised for mobile, it means that while you are right technically about how mobile browsers are supposed to work, and how sites are supposed to work, the real users just don't agree with you.
It seems easy to just add the tag and a few CSS rules - but what if this is a still useful page from 2005 which I have forgotten about?