Your experience at the farmer's market is surely equivalent to what most people would experience in Walmart.
Many humans will do anything it takes to make a profit and not care about who they are screwing over. If you think that's okay that's fine, but then go to Somalia and see how a lawless country works in practice.
Food safety in particular was mandated by populae request. I cannot wrap my head around free market believers like you who apparently think that humans are omniscient beings who have access to all information about every product and every seller they encounter so they can make informed purchasing decisions. That's just bullshit. You are a religious cult at this point.