The term Attic faith certainly seems to be rare, but not new. Ngram records 0 instances, but online sources attest to a definition in Webster's 1913 dictionary:
This same dictionary also lists several related terms, and references them in its adjectival definition of Attic, which was new to me:
a. 1. Of or pertaining to Attica, in Greece, or to Athens, its principal city; marked by such qualities as were characteristic of the Athenians; classical; refined.
(Arch.) a peculiar form of molded base for a column or pilaster, described by Vitruvius, applied under the Roman Empire to the Ionic and Corinthian and "Roman Doric" orders, and imitated by the architects of the Renaissance.
special purity of language.
a poignant, delicate wit, peculiar to the Athenians.
See Attic, n.
a style pure and elegant.
You go on to say,
I would like to know if it is a real phrase and its meaning is such.
It apparently is a "real phrase", in the sense that multiple authorities attest to it. I personally attribute more authority to Webster's than to the sources you listed, but any way around, multiple attestations are strong evidence. On the other hand, if by "real phrase" you mean do people actually say or write that phrase in modern English, then no. I never saw or heard it before today.