Maybe you're really slow at chopping onions? It takes like 15 seconds to dice an onion once it's peeled. Taking out, disassembling, rinsing, racking, unracking, reassembling, and putting away a food processor takes much much longer, any way you slice it. You're right, it's not even close -- manual dicing is always going to win for just a couple onions, unless you're already using the food processor for something else.