This painting is to remind other Americans that “Americans” come in all shades of skin color. Due to immigration issues, many Americans are treated unfairly. I personally have been affected by this issue. I am Mexican American. I was born in the United States and have been attacked for being thought to have been born somewhere else, not in America.
The wrestler is hitting Captain America, his fellow American, on the chin using a method known in some sub cultures called “chin checking”. That’s where a member of the group is hit once on the chin for doing something that was considered a mistake by his peers.