What amazes me is that you so confidently post that quote without realizing how terrible your understanding of it is.
This shows utter ignorance, go visit the place and understand the history. I kind of want to go on a long explanation, but its just not worth it, people will remain ignorant until they choose to educate themselves of the facts.
ps. If the Mayflower ship brings British settlers to the U.S. and they have a kid in the U.S, is that kid not American? A boer colony is just a place where early Dutch settlers settled in South Africa, just like those people arriving in the U.S. on the Mayflower.