BERLIN — Perhaps it was inevitable that as Turkey’s president, Recep Tayyip Erdogan, continued his authoritarian course, relations with his Western European neighbors would worsen. Unfortunately, he’s managing to ruin not just his own relationships with other governments, but also the Turkish-German community’s relationship with the rest of their country.

In recent weeks, many policy makers have audibly changed their tone in addressing German Turks and those who claim to represent them in Germany, culminating in a harsh statement from Chancellor Angela Merkel in late August. “We expect from people of Turkish descent who have been living in Germany for a long time to develop a high level of loyalty toward our country,” she said in an interview. “In return, we try to listen to their concerns.” For Germans of Turkish descent who have lived in this country their entire lives, that had to sting.

And yet she wasn’t lobbing wholly baseless allegations. The situation started to escalate in June, when the German Parliament adopted a resolution defining the murder of hundreds of thousands of Armenians in 1915 as genocide, a move that Mr. Erdogan protested vigorously. So did German Turks: Soon after, about 1,500 people showed up to protest in front of the Brandenburg Gate.

German Turks’ public support for Mr. Erdogan’s government soared after this summer’s coup attempt. Many came out into the Berlin streets after Mr. Erdogan called on Turks abroad to show their solidarity with him. Some 40,000 gathered in Cologne in a roaring sea of red moon-and-star-flags.