The charge of "Islamization" is at least partly correct, says Timur Kuran, professor of economics, political science, and Islamic studies at Duke University.
"Not only have Turkey's politics been Islamicized through AKP's deliberate policies, but Turkey's very large secular minority is under pressure to accept more and more religion in public life."
Kuran points to the strong support the country's mosques provided to the government during the failed coup attempt as an example of this.
"Never since 1923 has Islam been so central to the government's policies," he told DW.
Relations between Germany and Turkey were already strained prior to the leak over disagreements between the two countries in the wake of a failed military coup that took place in Turkey in July.
A post-coup crackdown, including the imposition of a state of emergency, have drawn criticism from Europe of the Turkish authorities' conduct.
"The Turkish government and the Turkish public are now used to snubs from Europe in general and Germany in particular. It is well understood that Germany disapproves of Turkey's increasingly authoritarian regime and of the ongoing witch hunt for Gulenists," Kuran said.