What are reasons to not sell alcohol free beer to minors? In The Netherlands, the law also prevents selling alcohol free beer to minors.

What can be reasons for this? Is alcohol free beer also addictive, and does it therefore attract minors to much to alcoholic beer? Or does alcohol free beer contain a substance that is also harmful to the (young) brain?
Alcohol free beer is not non-alcoholic, it does still contain some alcohol. It often contains around about 0,5%. A beer can be called alcohol-free from 1%.

To specifically respond to your situation I could not find any source saying that the Netherlands have an age restriction on alcohol-free beer. On the contrary the following sources indicate the opposite.

Sources (Dutch of course):

Ik ben 17 jaar, mag ik alcoholvrij bier kopen?

Mogen jongeren onder de 16 alcoholvrij bier kopen?