Leaving the "marxist propaganda" bullshit aside it was ( once again) a youth camp organised by the youth organisation of the (ruling) norwegian Social Democratic Party. Likening the Social Democrats to the Hitler Youth reveals such an breathtaking level of ignorance and disrespect for the victims that discussion basically becomes pointless.
And that is true for the silly attempts to justify it as well.
I suppose many Americans on here would (correctly) be angry if such a shooting had taken place in a camp of the Young Republicans and Europeans had been making these claims.