Hating Adolph Hitler is easy to do these days. He's an antique historical figure safely tucked away in the past who imagined and performed enormously evil acts. He and his noxious regime of Fascists were properly reviled and opposed by most of the world in a war which transformed the whole of global politics for generations. And Jack "King" Kirby was of course part of that war, both literally and figuratively.
Kirby and his partner Joe Simon famously drew their brand new hero Captain America socking Adolph Hitler on the jaw on the cover of the very first issue of Captain America Adventures way back in 1941. It seems bland enough to us now, but at the time it was a bit of a push since the United States was not looking to get directly involved in the coming war which we now see as having been inevitable.
But nothing's inevitable. Choices were made and the U.S. joined the fight in the nick of time we now see and joined with the Allies, and the forces of Fascist evil which threatened to drowned the world were defeated, and the new world order was established.
Jack Kirby fought for that victory over Fascism. He always seemed clear minded about the nature of the threat of Adolph Hitler and his kind and knew quite well the threat was not confined to the vile nature of a single human being.
A man is just a man until he can convince men of similar kind to join in a movement. Then it becomes the duty of every man and woman to stand up to the evil they see before them. It's the task of all of use to do as Jack Kirby did throughout his career, and that is to look evil in the eye and call it out for what it is and stand up for what is right. No one is perfect, but all men and women can do what is right if they only will.
Here is an article which further discusses Kirby's fight against Fascism. And here is another which has a lot to say to all of us in our own time.