Freenet's model places random content on every node. Sure, it may be encrypted, but if there's a sting and your IP distributes something bad during that sting, you will be investigated and possibly arrested/falsely accused.

It's the same dilemma that Tor exit node operators face. You are essentially loaning your IP out to the masses. Since this is what law enforcement uses to associate internet activity with individuals, there's a high risk that someone will eventually end up "borrowing" your IP to send something illegal.

Because Freenet is used for distributing CP.