To provide some balance, the article does state that the crew offered to inform passengers seated nearby, but wouldn't make an announcement to the whole plane and stop selling peanuts. I don't want to dismiss a potentially dangerous allergy, but I feel the passenger was having a bad day, and was probably aware of the policy and what would happen before boarding.
The representative added that cabin crew offered to inform passengers sitting near Willams of her allergy but that she later decided to buy all the packets of peanuts.
Eurowings website is reasonably clear that a peanut free environment is not guaranteed:
https://www.eurowings.com/en/informa...k%20on%20board.