A German news network (Called Focus TV) got the rights to this clip and made up a backstory. The backstory goes a little like this: a father secretly recording his angry, ADHD son playing his favourite violent video game. You can find a translated version of an article about it posted in November 2006 here. In it, there is a comparison made between him and a school shooting that took place in Emsdetten at that time. “Journalists” from Focus TV (Germany) used this as an example of an internet addict, claiming the kid to have been secretly taped by his father and to be undergoing therapy in addiction clinic. Naturally, this was not what “Leopold” understood to have agreed on when he gave approval for airing it on TV.By 2009, Focus Online, the Internet version of Focus, posted a video where the Angry German Kid made an appearance among other media. Here, he is presented as one of the most successful Youtube videos posted in German.
Credit to KnowYourMeme.com