Why Italian warships carried so many guns

Why did Italian destroyer and cruiser designs carry so many five-inch and smaller guns?

Because Italian naval designers had a strong cultural preference for heavily armed ships and rarely considered a battery large enough.

The heavy battery is an expression of Italian design culture rather than an accidental excess. Italian planners repeatedly valued adding guns to fast surface combatants and were reluctant to accept that a design already carried enough. The result was a recognizable national preference across destroyer and cruiser projects. This brief answer is a useful entry point for comparing national design priorities rather than judging armament counts in isolation.