That text is actually quite misleading. It never says that it's the snake that should be thought of as figuratively, maybe it's the Tree or eating a certain fruit that is figurative.

But, let us suppose that it is the snake they refer to - it doesn't disappear entirely. Because, a little further up in the catechism they mention this event again:

391 Behind the disobedient choice of our first parents lurks a seductive voice, opposed to God, which makes >them fall into death out of envy.

The devil is a being of "pure spirit" and the catholics believe that he was an angel that disobeyed god. Now, this fallen angel somehow tempts the first parents, who are in a garden (378). It could presumably only be done in one or two ways: Satan talks directly to Adam and Eve, or he talks through some medium. This medium doesn't have to be a snake, it could have been a salad.

So, they have an overall story of the Fall which they say they believe is literal, but they believe certain aspects of it (possibly the snake part) isn't necessarily true. Now, Maher's joke would still make sense in either of these two cases. It would just have to change a little bit:

"...but when all is said and done, they're adults who believe in a talking salad."

"...but when all is said and done, they're adults who believe in spirits that try to make you do bad stuff."

So, even if they say that they don't believe in every aspect of the story, it smacks of disingenuousness. It's like saying that I don't believe the story of Cinderella getting a dress from a witch, but that there were some sort of other-wordly character that made her those nice shining shoes.

But, they don't even say that the snake isn't real.

I don't see what your second quote shows about my argument that if they don't believe in the snake, what keeps them from saying that anything else is also figuratively (such as the existence of God).

It's only fair to compare like with like. I'm sure that I can find some people, who profess both a belief that >evolution is correct and that monkeys gave birth to humans; and yes, I am aware that this mean they have a >badly flawed idea of what evolution is.

So, in fairness, if you're going to be considering only leading evolutionists in defense of evolution, it makes >sense to consider only leading theologians in the question of whether Genesis is literal or figurative.

I agree there is probably someone who says that evolution is true and that people evolved from monkeys. But, to compare likes with likes here, you would have to find a leading evolutionists that said this, to compare with these leading christians that believe the snake was real:

But the serpent was “clever” when it spoke. It made sense to the Woman.1 Since Satan was the one who >influenced the serpent (Revelation 12:9, 20:2), then it makes sense why the serpent could deliver a cogent >message capable of deceiving her.

Shouldn’t the Woman (Eve) Have Been Shocked that a Serpent Spoke? | Answers in Genesis

… the serpent is neither a figurative description of Satan, nor is it Satan in the form of a serpent. The real >serpent was the agent in Satan’s hand. This is evident from the description of the reptile in Genesis 3:1 and >the curse pronounced upon it in 3:14 [… upon thy belly shalt thou go, and dust shalt thou eat all the days of thy >Life ].

Who was the Serpent? | creation.com

Maybe it is wrong to label these writers as leading christians (the latter quoted is a theologian, though). So, let's say they are at least popularizer, if that seems fair to you? If so, can you find any popularizer of evolutionary theory that says that man evolved from monkeys?