Because Euro inflation is not specific to Germany. A “German” Euro is worth the same as an Italian one, for better or worse. Therefore, to state that there is even such a thing as a German rate of Euro inflation any longer is erroneous. You know, it’s that monetary union thingie that preceding the political union thingie that got underway back in the nineties and became official currency in 2002? Many don’t like it and would prefer a return to the Deutsch Mark, but it is what it is, unless and until it isn’t.
Fail - and the failure is due to you obsessing about something you call ‘euro inflation’. The article is talking about price inflation. The currency the prices are marked in isn’t particularly relevant.
Prices for many things in Germany are different than the prices for the same things in Italy even though they both use the Euro to denominate them. The changes over time in those prices are often also different. Understanding local price inflation is an important tool for governments, especially if certain benefits and transfers are linked to it (as they are in many EU countries).
Is that really so hard to understand?