Earlier quoted context omitted.
If the statue is the Drusus Germanicus I think it is, he was a Roman general and politician who earned the agnomen Germanicus for leading successful military campaigns in Germania. See also: Scipio Africanus; he got that name for conquering Carthage.
It didn't look like the famous one, at least to me. Romans were notorious for reusing names. Even if it were the famous one, he was, in fact, in Germany, yes?
You're not alone in thinking that. The article says the sculpture might actually be Pompey, not Drusus Germanicus. Evidently there's no name written on it, so it was probably catalogued as Drusus Germanicus because somebody thought it looked like the Drusus Germanicus, but they may well have been wrong.
> Even if it were the famous one, he was, in fact, in Germany, yes?
He certainly was. As far as I'm concerned, Germany is a perfectly fitting place for a sculpture of Drusus Germanicus.
My main point here is you can't assume a Roman was from the place they were named after. They might have been, or might not have been. Generally speaking, it's not even a given that a person named Germanicus was ever in Germania nor had any ancestry from Germania. The son of Drusus Germanicus was the Germanicus, the most famous Germanicus. The Germanicus to whom you can refer with the name Germanicus alone. The Germanicus inherited that name from his father Drusus. Complicating the matter, the Germanicus then went on to lead numerous military campaigns in Germania as his father did before him, but he already had the name Germanicus as a child, inherited from his father Drusus. There are actually a whole slew of Romans with the name Germanicus and many of them likely never set foot in Germania. Emperor Claudius (brother of the Germanicus and son of Drusus Germanicus) had the name Germanicus as well, but he was probably never in Germania. Nero and Caligula were also named Germanicus. A ton of Romans were.