I’ve made similar thread a while ago, when single stack spam just started: AH add-ons that are ruining Classic
Since then it turned to worse. Many players are intentionally posting single stacks to annoy other players, so they would have a choice either to buy overpriced single stack or spend 10 minutes scanning pages. Such add-ons should not be allowed in Classic.
Even though “technically” AH add-ons existed in vanilla, so did LFG add-ons. Yet none of them were popular enough to cause problems. Today Blizzard has disabled LFG add-on and AH add-on is already causing big problems. Players should not be forced to use add-on in order to be able to use auction house.