E - what mashed potato said + good public speaker, had a feeling for the crowd, external world was the real world for him after all. Also the ability to persuade people to your own vision is more E than I. Being an extrovert is not about being loud. I'm a very calm and quiet person most of the time and I'm sure I'm an extrovert. My real world is the external world. Also he was depressed and fucked up most of his life so he wouldn't be a typical extrovert anyway.
N - he was obviously intelligent and able to understand complex theoretical issues, his vision, he had Ni written all over him
T - do you guys know any NFs? They don't have the ability to be evil. They just can't do it. It makes them physically sick. It produces them pain. They can only hurt people in tremendous amounts of anger and then regret it later for the rest of their life. You can't be angry all your life. Every NF I've ever known was hypersensitive to people's needs and feelings. They are the best of people.
J - I see there's no doubt about this
Also he was obviously Fi. Had his own image of right and wrong and because he was an extrovert he projected it into the world with ruthless Te. He was aware that morals are relative, that life makes no sense, he had no sympathy, so that basically makes the world your playground. In his mind he was doing the right thing, and to me some of his ideas actually make sense. He ultimately wanted us all to be pretty, tall, blonde and smart. In most ENTJ minds the goal justifies the means.
Cost benefit analysis:
cost: couple of million people, huge amounts of resources, setting the Earth back 10-20 years
benefit: ubermensch - if he managed to get his vision through to the end, we would all be genetically modified to be beautiful, healthy, having huge IQs and improving the world 10 times faster than now. Imagine a world of millions of sexy Einsteins and Teslas, that's what he saw, instead of deaths before him. The benefit is setting the Earth hundreds of years forward because everyone would be supersmart, superhumans.
The benefit outweighs the cost, time to implement vision(Te). An ENTJ is the only one who would dare to do this, to play God.
Also, ENTJs dismiss stupid people almost in an inhuman way. If you know nothing, you have no value in my mind. I know I would rather read the internet all day instead of chatting with most sensors out there.
There, I've uncovered the secrets of the evil ENTJ mind. I hope I didn't degrade ENTJs more in you mind. We can be awesome when we're on the "right" side. The thing is, we're not sure if there's a right side.