[mortallywounded]

I believe Satoshi was a cypherpunk and a remailer dev. Cypherpunks had a history of doing things anonymously on the mailing list and even trying to out one another (a sort of game).

Furthermore, as a remailer dev Satoshi was all too familiar with what happened with the penent remailer[1]. He knew such services will become a legal target by the powers that be. This is why Satoshi even said we "kicked the hornets nest" when Wikileaks/Silkroad began accepting Bitcoin.

He knew the powers would be coming.

[1]: https://en.wikipedia.org/wiki/Penet_remailer