Google Loading Cookie When Using Firefox RSS Display

Nathan Weinberg covers a report from LegRoom.net that shows Google is loading a cookie on your browser that won't expire until 2038 when you access RSS feeds via the Firefox 2.0 RSS display. The real issue here, as I understand it and as LegRoom suggests, is that Google's favorite icon is loading a cookie on your browser. Since Firefox 2.0 is using the favorite icon in the RSS display, the cookie is automatically being added to your computer. Firefox is also calling the other RSS readers for their favorite icon, but I believe those favorite icons do not set a cookie on the computer. So why is Google setting a cookie for their favorite icon?