I lived in Germany for 3 years and have been back there several times over the years. Germans, and Europeans in general have a much higher driver education program than in the US, and especially Canada where driving is a joke.
My aunt who lives there retook the test 3 times because she failed, and not only that, she had to paid thousands of marks just to get it.
A lot of German cars are highway mega monsters, even a diesel Jetta there travels at 200-220 km/h if it desires. When you move up a class and get into the Audi's, BMW's, Mercedes, all those cars are easily capable of 240 km/h + travel.
Sure it's dangerous, but that's how you drive up there. In fact I would not even consider that dangerous compared to how cars or motorcycle drive in Italy let's say, or even Poland, a country with a high population, limited space, and non developed road ways. I was in Poland and my cousin drove me from Lodz to the Baltic on a two lane road most of the way. I almost shit my pants and how he was driving, passing cars, flashing lights, 24/7.
It all comes down to education and intelligence at the end. Germans are a highly educated people compared to most countries, especially North Americans. Of course if that happened on our highways it would be dangerous, it's dangerous to just drive the speed limit and people cut you off or don't move out of the way because they are asleep at the wheel or don't even see you.
In the end it all boils down to checking your mirror. You check your mirror, you see a pair of headlights approaching you, maybe even flashing, you gtfo of the way, it's that simple. To get the same effect in North America you need to use the horn, flash your lights, possibly pass them from the right, or install a train horn kit like I'm planning to.