> thinking they're terribly clever because they're only pretending to be stupid

That's the whole problem with the SA attitude: irony.

"Irony is appropriate only as a pedagogical tool, used by a teacher interacting with pupils of whatever sort; its purpose is humiliation, shame, but the salubrious kind that awakens good intentions and bids us offer, as to a doctor, honor and gratitude to the one who treated us so. The ironic man pretends to be ignorant, and, in fact, does it so well that the pupils conversing with him are fooled and become bold in their conviction about their better knowledge, exposing themselves in all kinds of ways; they lose caution and reveal themselves as they are--until the rays of the torch that they held up to their teacher's face are suddenly reflected back on them, humiliating them.
Where there is no relation as between teacher and pupil, irony is impolite, a base emotion. All ironic writers are counting on that silly category of men who want to feel, along with the author, superior to all other men, and regard the author as the spokesman for their arrogance.
Incidentally, the habit of irony, like that of sarcasm, ruins the character; eventually it lends the quality of a gloating superiority; finally, one is like a snapping dog, who, besides biting, has also learned to laugh."