Why Horizon produced frigates for France and Italy

Why can the French and Italian Horizon ships be classified as frigates rather than destroyers?

Their design intent and sustainment fit air-defense frigates, while Britain sought a larger, more independent destroyer for expeditionary operations.

In this classification, the French and Italian Horizon ships are defined by design intent and sustainment rather than their official labels. Britain wanted a larger destroyer able to sustain distant operations, while its partners were content with air-defense frigates that could be called destroyers. Britain also expected influence proportional to its larger intended purchase, but France and Italy sought their own work share and control. Divergent operational requirements, quantities, and industrial expectations therefore made a single multinational ship increasingly difficult to define.