I can understand your frustration since this topic come up all the time in our markets. To help I'll try to expand on the various reasons for having liability insurance. Most common claims are not for food borne illnesses but are usually for stand damage or injury. For the few insurance claims in markets I've been in 2 were from wind blowing canopies either onto a person or vehicle. In one case the wind lifted concrete blocks holding a canopy down and hurled one through a vehicle windshield.

Another claim was a simple case of an item falling from a market table onto a customer's foot, breaking a toe bone.

For your own benefit you want liability insurance regardless of what you sell. A customer of mine set a tray of plants on her car trunk and then argued that my tray scratched the paint surface on the trunk.

A pet or child might think that the leaves on your shrubs are edible.

Your vehicle may somehow move and cause damage to property or people.

Someone might injure their back just trying to lift a plant or they might hit their head on a pole or trip over a shrub and loose a tooth on the pavement.

The amount of insurance needed is more up for debate. In both markets I'm in the Borough requires that both the market and individuals have insurance. In one of those markets the market insurance company requires that each vendor have the same amount of coverage as the market.