“Virtually the entire story except the bookends are in World War II because we all recognize we have one chance to tell the origin story of how he became Captain America, you can’t tell a modern story and then go back and tell the origin story. If you’re going to do it, let’s do it. Let’s do it first. Everyone wanted to tell an origin story. There was a version where it was a modern story and it didn’t work.”
Director Joe Johnston
So Red Skull, as Captain America’s greatest foe, is the right pick!