>8000 km away from USA, how is Iran a thread to the United States exactly?

I'm confused. He is quantifiably one of the most evil people on the planet, with a long list of human right abuses. Yet, what business is it of the United States to kill him?

He's responsible for the death of thousands but you want America to turn the other way. And then America kills one person, suddenly you are calling them out?

(yes, i am making a moral argument. No it's not the strongest answer. But it's a) the most compelling b) i'm not a general, but i'm sure there are plenty of strategic reasons too).