How to decrypt using public key? Can anyone decrypt ciphertext using a public key? I always thought we can only decrypt using a private key. In that case, what does this line in the RLPx documentation mean?

Receiver receives the initiator handshake and decrypts it with its own public key. 

Is the author talking about verifying signatures?
That's actually a typo, you'd use your private key, not your public key, to establish the secret used for ECIES. File a bug report on the documentation!