Yeah, this clause has been in the EULA since the release of the game and is there due to the second-hand sales market...basically no game company can prevent you from selling or passing on a game to someone else as long as you don't keep a copy.

Others have raised this on the CSF forums over time and the response has always been the same...it relates to the CD's and the packaging, not to the account created with the license key that came with said packaging. You can sell the box and cd's to someone else but the account remains in your name and owned by Blizzard, they merely license back the use of the account to the person whose name it's in.