Your quote is about the reverse direction, traffic offenses in the US being served to someone in Germany. The OP is asking about a ticket from Germany being sent to the US. I agree that it will not be enforced but depending on how big the fine is he might have issues traveling back to Germany or if it crosses some threshold even the EU.

@Nick Actually, all EU driver's licenses share a common format and are valid between each country. bmvi.de/SharedDocs/DE/Artikel/LA/… mentions 3 conditions: not being from the EU/EEA and not being in german and not being conforming to a special international agreement on road traffic. The first and second are clearly not fulfilled but the third point might.