Despite what the article says, the International Union for Conservation of Nature (IUCN) doesn't consider the wolves that inhabit the Eurasian continent to be endangered [1].
They have individual ratings for different regions on that page, and they rate Germany/West Poland as Critically Endangered, so the article isn't just making it up. Maybe a more accurate wording would be "endangered species in Germany".
Some interesting notes in the summary: 1) wolves are one of beneficiaries of political instability (see the section on Balkan states). 2) in case of need, rescue from the Russian population is possible (section 7).
Is not endangered as species, but locally can be different. In 2016 there were only 46 reproductive pairs in the entire Scandinavia for example; and Denmark has in 2017 their first and only reproductive pair in 200 years.