Why so many German warships were called frigates

Were linguistic or translation issues responsible for Germany calling so many warships frigates?

Mainly no; the label was political, though German naval rank terminology reinforced it.

The broad use of frigate did not result chiefly from a translation accident. Political presentation was the main reason for applying the label to many German warships. Rank traditions such as Korvettenkapitän and Fregattenkapitän reinforced the vocabulary. The classification therefore reflects institutions and public politics more than a precise description of hull size or mission.