Wasps in first line are predators, also needed in an healthy environmentm same as any other predator. Are only agressive when are in risk their nest or in selfdefense. It is typical in a picnic, a wasp can also appear to inspect food, but then it is also common for people to hit the wasp and it is normal that then defends and itchs. If he had left him alone, nothing had happened.

Aggressiveness is a human invention, an animal is never aggressive by default, when its nature and its territory are respected. There even existing videos abut hornets as mascot.