Why should anybody mind about a pipeline extending across what is essentially uninhabited scrub and desert? The area you mention is around 3,500 sq miles (for comparison, about seven times the size of the Brecon Beacons NP) and has around 8,000 inhabitants. So, a little under half a square mile (320 acres) each. And there is no room to accommodate a pipeline? Or does the land have some "spiritual" connection which means it cannot be defiled?
As I understand it, the main objections are on environmental grounds and are based on the premise that "pipelines can break". Quite true. So really we're back to the Green lobby. Because something has the potential to cause damage we don't use it just in case. These protests are, in fact, little to do with native Americans. If you read this:
https://daplpipelinefacts.com/dt_articles/the-dakota-access-pipeline-does-not-cross-land-belonging-to-the-standing-rock-sioux/
You will find on page one, paragraph one, line one,this:
"No part of the pipeline will be installed on the Standing Rock reservation." (accompanied by a map).
"Environmentalists" need to understand that the world needs to shift stuff about (unless, that is, we all live in caves in the cold and dark).