Surely, they meant to say:
If that's what they meant, I disagree. The LCD-2 is more sensitive than the HD-800 (but it is less sensitive than the HD-600). Try connecting an LCD-2 to a Sansa Clip+ or an iPod. Now try the same thing with an HD800. I've never had the opportunity to try this with an HD-800, but I've read many accounts of people using even the iPod Shuttle to drive the LCD-2. Of course, no one says the LCD-2 sounds its best on 30mW, but I've never heard anyone commenting on an HD-800 sounding "surprisingly good" on 30mW.
The LCD-2 will, however, reward the user who supplies it with more power. The more power you give it, the better it sounds - up to the maximum permissible 15W per channel. In my experience with the LCD-2 rev.1, as power is increased, the bass control improves as one would expect, but so does the mid and treble - yielding higher resolution across the spectrum, which improves the imaging and stage, as well. But the greatest improvement is one of dynamics, giving you more slam or punch with recordings that call for it. Giving you drum hits that have serious impact and even a more percussive quality when piano is played loudly (fortissimo). In short, more power gives the LCD-2 greater detail and dynamics across the spectrum.
Mike