I'm being tongue in cheek here, but to support your point a little, if Bitcoin was not generally anonymous in nature, we'd know who Satoshi is.. no? :-)
Does Satoshi regularly receive bitcoin donations and convert them to USD? If he did I'm reasonably certain that someone could figure out his identity. The list of people that the US Govt (as an example) wanted to find and couldn't trace through bitcoin transactions is very short...
