This seems to be a concession to web browsing. When visiting web pages, many Mac users complain about images showing up as too dark, when they appear "just fine" on Windows browsers. Safari was supposed to fix this, but third-party browsers like FireFox and Camino never bothered to deal with color correction, so this default is a work around, since so much work is done on the Web anymore. /-: (Funny how Windows users never complain about images appearing too bright or washed out. I guess Windows are used to problems dealing that OS. (-: )

(Not that this should 'ffect me much, I'm using a ColorSync profile on my home machine that changes the white point to a grey tinge to match the lighting in my apartment anyways.)