The mother Marge Simpson creates the group after Homer Simpson gets hit on the head by baby Maggie Simpson. Marge blames the incident on the violent content in the fictional television show Itchy and Scratchy, and starts a campaign to curb violence on television.
The word SNUH appears in a later episode, in a clip from a campy 70s Radioactive Man movie. The word appears, in the typical fashion of superhero movies of this era, in an explosion bubble and accompanied by sound effects.
ZUFF! PAN!! SNUH! BORT! POOO! NEWT! MINT! ZAK!
In another episode, when Marge tries to make Homer promise not to buy Lisa a pony, "snuh" is one of the nonsensical words uttered by Homer instead of making an actual reply.
Perhaps the comedic value of SNUH is because most acronyms are chosen to sound catchy while an awkward assortment of words are used to represent the initial letters (ie. (backronyms). SNUH, however, fails in both respects -- having an unattractive pronunciation and a contorted expansion of words -- causing observers to wonder why such a strange name would be intentionally chosen.