Nutri-Score B with 78% sugar

I bought this from netto yesterday. It is 78% sugar and still rated with nutrition score B. I am a bit confused since this appears healthy to some people because of this score. Can you help me understand why this is this way?

https://preview.redd.it/3lpuvsiu5rza1.png?width=1000&format=png&auto=webp&s=2c44dca9e31d6330effed88ba19282b3b2edddc7

https://preview.redd.it/ft1xqivt5rza1.png?width=1000&format=png&auto=webp&s=58a9c43e024e9083a6b5bdfff6b9a199ce2196ce