Such a decision was made by the company’s management due to the fact that loot boxes are banned in both countries. They are considered gambling mechanics in Belgium and the Netherlands.
And initially Activision Blizzard did not take an official position on this issue. She simply removed the ability to pre-“register for the release of the game” in the mobile stores of the mentioned countries.
The Dutch edition of Tweakers drew attention to this. It also asked the company for a comment on the situation. In response, she confirmed that Diablo Immortal will not be available in these regions.
The official reason is: “This is due to the current working conditions of the games in Belgium and the Netherlands.”
By the way, Diablo Immortal, apparently, will appear in Russia. In the local Google Play, you can still pre-register for the project.