I'm using a 15" Retina MBP with 2880 x 1800 resolution...
The text should not wrap into two levels at a reasonable amount of browser zoom, it is a design flaw. There is plenty of lateral space remaining, it does not have to wrap.
If you doubt this, find a Retina MacBook Pro, which I'm sure are well represented among your userbase, and try to read the new FT at 100% zoom. With the laptop in my lap it's like trying to read a newspaper at full arms' length.
Not sure what your issue is. If you like, please post a full screen shot of your screen with this happening. Very hard to tell with just a snippet of your screen.