Have naval officers become less aggressive?

Have naval officers become less aggressive over time?

No. Professional education channels aggression according to role, with destroyer officers historically freer to display it than cruiser officers conducting diplomacy.

Aggression remains useful, but command requires knowing when and how to apply it. Destroyer officers in some periods could cultivate an openly combative style because their ships were tactical weapons. Cruiser captains often represented the state abroad and therefore had to control the same instinct during diplomatic work. The difference is disciplined expression rather than a simple decline in fighting spirit.