Yeah.
Even though I'm a historian and a sort of latinist I understand perfectly why especially Pasolini - or propably any modern person for that matter - would find those mythological characters outright goofy and silly.
I also think they represented to Pasolini the old and more superstitious reality of a world long gone by, pseudo-realism that didn't have much to offer to the more modern world and it's inhabitants. Hermes was a jokester also like you said.

Ah, ok. Thanks for the info!
If I recall some of Greek mythology correctly, Hermes was a bit of a jokester. Maybe that explains the silliness.

The character is credited as Angelino - the Messenger. The word derives from Late Latin angelus "messenger of God," which in turn was borrowed from Late Greek ngelos. It of course bears similarities with figures like the Greek Hermes also.
So that character was essentially Pasolini's interpretation of a heavenly, winged messenger who brings the message of a coming of the Saviour - in this case in a Marxist sense - to the bourgeoisie family, like Gabriel told Virgin Mary about the coming of the Christ that she would give birth to.