From their homepage:
This utility will turn your Windows 9x or NT desktop icon text backgrounds transparent; allowing your wallpaper to show through. It will also allow you to easily change the icon text to any color.
If in fact it is only able to change it to the color of the background, that's kind of misleading and not as useful as it would be (and a really weird limitation, having the icon and desktop colors linked).
I don't think "most" users necessarily use a background wallpaper. I certainly don't since it causes a noticeable difference in desktop performance (refreshing icons, closing windows to reach the desktop, initial desktop display on boot) on every system and every Windows version I've ever used. If that's really the very limits of how possible it is to change the text color, then I certainly don't blame people who make it available but it is pretty lame. I would think if you can turn it transparent, or force it to show the desktop color through the wallpaper, you can set it to a color.
Of course, I also don't see the point of transparent text so you can see the wallpaper, obviously it means you can see the wallpaper instead of text and just see the icons (and even make those transparent) but what's the point of a desktop that you are always worried about keeping clear so you can see the picture?