I can see why being promised cash in exchange for accepting the plan might not seem to impressive from the perspective of the natives given the historical relationship. The reservations they were moved to were, in many cases, not capable of sustaining their population and so additional funds were part of many treaties to allow them to purchase food and other necessities. These disbursements were chronically late, less than promised, and fraud, embezzlement, and other corruption plagued the Bureau of Indian Affairs. The term Indian Agent pretty much implies malfeasance and self-dealing.
Moving on, generally, part of the approval of a project includes an Environmental Impact Assessment. It's hard to generate a lot of trust in an analysis that is written by the company proposing the project and reviewed by government agencies who are in those company's pockets. How much effort goes into creating these documents and/or carefully reviewing their veracity? In the case of the Macondo well (Deepwater Horizon):
Oil companies put whatever in their exploration plan and if all goes well the federal agency will rubber-stamp it. Consider this: In their Deepwater Horizon exploration plan that MMS had approved, BP had pledged that they would protect sensitive species including walrus, sea otters and sea lions — all cold-water species not found in the Gulf of Mexico. They did a cut-and-paste from some Arctic document.
http://www.huffingtonpost.com/subhankar-banerjee/bping-the-arctic-again-fa_b_926856.html
Response procedures aren't all that impressive, either. Technology hasn't changed much in decades. Floating booms, surface skimmers, giant paper towels, dispersants, etc. The emphasis seems to be on removing visible evidence of oil on the surface of water or land with little actual removal. They frequently make claims for effective recapture and cleanup, but historically seem to end up only cleaning somewhere in the single-digits percentage of the spilled volume. Investing in cleanup technology costs money the oil companies aren't particularly interested in spending and independent companies specializing in such work are few and far between (being dependent on a totally random revenue stream). PR firms, on the other hand, are plentiful. The
appearance of everything being fine seems to be their top priority. So much so that during the gulf spill, they refused to provide (or even
allow) workers hired to clean beaches to wear robust safety gear so that cameras would show images that made the problem look minor.