In a nutshell they don’t have to build this pipeline. They can continue transporting oil by truck or railroad like they’ve been doing for decades (tho that’s risky too). They also want to frack on their land which puts their underground water supply in big jeopardy. Also at some point this pipeline goes underneath the river and that too is a major disaster waiting to happen.
This is their land that they’ve been living on for over well over a 100 years and these actions are in violation of the treaty the U.S. signed with them. They are being brutalized by the petroleum workers and police alike for simply defending their land and water supply. Wake up history is repeating itself.