about the dude being german/iranian one thing to note is that iran almost never releases one out of citizenship. if you're father is iranian, you are iranian citizen by default, no matter where you are born. so a lot of iranians living elsewhere never change citizenship or are forced to live with a dual nationality, if that is even a possibility. to become one nationality or the other, in the case of iranian double passport both countries have to agree.
i have a friend in his 30s that was born and raised here and he's still an iranian citizen. he doesn't speak any languages spoken there, nor was he ever in the country. he's only identifiable as iranian by his name and passport. he still has to get his papers straight every 6 months or so and is not allowed to work for the same wages because he is technically still a second generation refugee. if for some reason his papers expire or don't get renewed because he gets a new asshole supervisor, he can be flown out to iran, but not before he is put into jail for approximately half a year to detain him until his scheduled flight goes off. this sounds crazy but it is actually a complicated legal thing in his case and admittadly he did some shit in his youth that made the whole ordeal almost impossible now(if you fuck up in germany before you become german you might as well forget it, or keep it low for years and marry a german person and make kids so you're allowed to stay pretty much indefinetely as long as you remain married or in the relationship). but he should have been german in the first place.
you see unlike the u.s. that gives citizenship to you on the grounds that you are born on their soil, germany gives citizenship based on parent nationality. it was hard to become a german citizen for a long time and still is not that easy if you come from out of the eu, but being born here means nothing. so to actually even have a dual citizenship as an iranian in germany by default means one of your parents has to be german. some families have been staying in germany for three generations until one of them was granted a german passport, often only by marrying a german. i admit this is also due to some unwillingness amongst some immigrants to become german citizens, but most people that have been living here all their lives of course want the same rights at some point, assuming they were good law abiding citizens the whole time.
just to put the whole dual-nationality thing in perspective. now the guy also had a german passport which means he had a lot less problems than my friend. it's actually bizzare that he seems to have been some kind of german supremacist of iranian descent. to me it only shows that people that hate humanity and themselves will kind of adopt whatever crazy way of thinking they see fit to justify their actions before themselves.