Many states have laws outlawing flashing headlights as well. this link is for Washington State
RCW 46.37.280
There are too many laws in this country, but sometimes they enact them for good reason. This, in my opinion, is one of those times.
this article is very informative and well written. Don't be "that guy" who puts his personal safety over everyone else's
https://crosscut.com/2013/11/bicycle...linking-lights
Keep in mind the bicycle fatality rate in German is a fraction of what it is in the US.
Germany vs US bike stats
Oh, and the Germans tend to not wear helmets
German bike helmets