Cloud Easton, Reading Question

From the reading: The land in American religouse experience

Within this reading there is much discussion on the manifest destiny and how it relates to the early Americans spreading throughout the colonies. While it takes on a hard analytical view of things and what happened, there is something tha escapes my thought process.
"For the most obvious reason for dominence of the land at the beginning, for those who cam when space of America was wilderness, was that it was clearly there-can could not be ignored."
My question on this statement is how to interpret this. Was it simply a "we found it so its ours" mentality, or rather a "well we have no other choice might as well claim it?" These are the view points i cannot derive. The words i get. Factually I understand what is being stated, but how to take the implications I don't understand at all. The talk of the first peoples who landed makes it sound as if it were a first come first serve basis, but then at the end the comment sounds as if they had no choice in the matter and had to take the land. I am so confused @_@