You're right about the non-reflective background, especially if you are trying to isolate your target, but in this case it was more a quick way of showing the difference between the lenses.
For anyone interested in learning more about macro photography, including use of flash, I recommend checking out the following sites:
and click on the "Learn & Explore" tab and then Macro;
and check out their forums, and
(lots of different forums).
I'm amazed at the amount of information that's out there!
Tight Lines and Happy Snaps!