That happens with any anti-aliasing. After using a Mac for some time, what bothers me about ClearType to no end is that for some fonts, the colors are painfully visible without looking closely. Without exaggeration, it looks like shit smeared on the text.
Regardless: am I the only one who doesn't see much value here? The icons earlier were arguably more readable, but the colors are nonetheless a little distracting. And I have a strong suspicion from comments (some very positive, some like me much less impressed) that these images are being tuned very heavily to a particular LCD design, or pixel pitch, and aren't as generically useful as people think.