Thats his style, that's what Nick does. Gotta take extreme measures to ensure the safety of the earth, hence why they had the nuclear rocket on the Helicarrier.

He really doesnt care about the heroes, and merely uses them as tools against any threats. Its evident in the avengers initiative.

To claim he doesn't care about the heroes is hugely unjustified. Fury may ba calculated, but cold he is not. After Tony's successful manoeuvre of the nuclear missile everybody cheered in delight, but Nick looked mournful...

oh really. Be interesting how they talk about his 'revival'.