What does it mean?

When I first saw this image, I first thought of the europeans(whites), colonizing over the Africans(blacks), in some ways I thought it was very racist, because all the black africans could do was hope that their homes weren't colonized. It wasn't fair for the africans to be kicked out of their homes. Now, let's talk about foot step. When I think of someone putting their foot down in that way, I suppose that that person would be knowing what he or she is doing. And in this case I suppose that the person also want everybody to follow his or her actions in that way, so his or her deed is just let loose. When I think of colonizing, I think of ruling, and this lead my head to one person ruling another, like bullying. So in the end, I think of colonizing as bullying.