The point was "But why is anonymity necessary?"

Not just freenet. A "secure anonymous pseudonym" can be used anywhere you have a system for anonymous posting or file sharing.

You need anonymity in order to have freedom. It's that simple.

Besides, it's a great defense for the small guy against the super power greedy types.

You should support and defend anonymity if you are a flag waiving, freedom loving person. The "press" keeps it's sources secret, and you would defend that wouldn't you?