While Germany "only" has two types of terrorism. First one is ISIS. they "only" succeeded one terrorist attack. The second one are "Reichsbürger". These are people who believe they live in in the Kaiserreich (the Imperial German Reich 1870-1918). They kill cops and have own laws. BUT BUT the casualties are really really low. Because no one can get a gun without long and detailled background checks which can last to 6 months. Basically the police is much more powerful and nearly no situation situation escalated. I think the highest casualties were 28 kills in a year.

In America everyone can get a gun with "background" checks. Heavy machine guns and automatic weapons. Everyone who commits a bloody mass shooting is a terrorist. And there are many """disturbed""" individual who can commit to easily a crime. In America at least 28 get killed a day