There were no Sim-Swaps, at least not from the Student. Later it was revealed that he simply bought the Data & published it. The Hacking did somebody else.
That doesn't make much sense. Why would a student, presumably with little money, buy something that seems likely to command a pretty high price, that he has no use for other than to post anonymously on the internet?
I don't know him, so all i can is guess. All I know is what the News in Germany reported. According to them he just acquired the Data he published. The reasoning behind it is unknown to me, if there was any. In the Media Coverage he doesn't really appeared that smart. Maybe he did it just to brag about it, or he was hoping to extort the people and wanted to prove that he has the material, or it was political because the most victims of him were from the left.