There is another author who said that all of Homer and Hesiod is lies. Not just lies, but profane, blasphemous lies. This was not a Christian fundamentalist, or a 19th century academic armchair historian, but Plato. In book II of the republic, Plato's Socrates has just talked about which stories are better and which worse, and his discussion partner (Adeimantus) asks which stories. Plato's character and narrator (i.e., Socrates) responds:
Οὓς Ἡσίοδός τε, εἶπον, καὶ Ὅμηρος ἡμῖν ἐλεγέτην καὶ οἱ ἄλλοι ποιηταί. οὗτοι γάρ που μύθους τοῖς ἀνθρώποις ψευδεῖς συντιθέντες ἔλεγόν τε καὶ λέγουσι/"'those,' I said 'that the two poets, Hesiod and Homer, and the other poets tell to us. Indeed it seems clear they told (and still tell) to humankind the false tales they crafted."
The word I've translated as "tales" here is mythous a form of the word mythos. So for Plato (and possibly Socrates) it wasn't just the story of Achilles, but every single myth told by those like Homer and Hesiod which were lies.
It would appear that Plato, an actual Greek who actually lived during the time and place in question thinks you are wrong. In fact, you aren't just mistaken, you've got it backwards. These myths are not just stories, they're lies.
The same is found elsewhere, as I already mentioned in another post. In one of the extant fragments of Varro's Antiquitates rerum divinarum we find him not only saying the same thing, but classifying types of theological discourse into "genres" of sorts, the worst of which was myth (mythice).
And when we don't have philosophers disparaging myths, we find historians embarrassed by them. Like the early 19th century rationalist biographies of Jesus, in which the authors tried to rationalize the impossible parts of the gospels (including the resurrection), Livy, Plutarch, and other both castigated those like Herodotus for including too much myth while they themselves explained away/rationalized mythic stories such as Romulus and Remus being raised by wolves (that was explained by a mistake about the names of the people that adopted these two mythic founders who never lived).
We find comedy developing by making the gods look foolish, playing on Homer and other received myths for kicks, and eventually the birth of the early novel doing the same. There's even a parody of Homer (it's great, actually) called The Battle of Mice and Frogs.
Meanwhile, Socrates was killed for profane actions as were several others at that time (one of religious crisis). The romans executed thousands of witches. They executed christians for not participating in civic cultic practices. They participated regularly and diligently in all kinds of religious rituals and practices, both for particular occasions and in regular devotions. The gods and religion were important enough to execute those who violated the sanctity of ceremony or, like Andokides, was put on trial for another type of sacriledge, and the rich paid enormous sums to build statues, temples, etc., to honor the gods. Religion was taken quite seriously, to say the least.
Why, then, do we have a tradition going from before Plato to until Constatine of mocking the myths, explaining them away, or equating them with sacriledge and profanity?
Because this idea of sacred myths was for the most part (albeit not entirely) created about a century ago (a bit more, actually) until those like Frazer, Michelet, Bachofen, Tylor, and even Campbell and Eliade stopped reading their own prejudices and biases into the myths and started actually seeing the difference between religions of practice and their own cultural conceptions of religion (religion of the book, or of scriptures).
