Well here's an alternate version of the story:

The islands up to Orcas were disputed by French and Americans at the time when French Catholic Missionaries committed atrocities and forced assimilation religious schools, later Americans took the land, and created the reservation system. There were many injustices, but that history is older than this story.

In the last century, Washington land wasn't super valuable outside of logging, and some people of the Lummi nation are struggling and sell the title of some costal land for money, thinking little of it. In the 90s tech makes it big and there's a population boom, suddenly costal development of nice homes are incredibly valuable, and developers are putting in homes in Sandy Point - a strip adjacent to Lummi nation.

The tribe now feels like its unfair, they ought to be paid a lot more of this now-very-valuable land. They claim the sale was not valid, the land is still Lummi. Although there are records of the sale on the American side, the Lummi story is that the sellers were orphans, part of the tribe by heritage but without written records. They weren't authorized to make such a sale, and so it should still belong to the tribe, the sellers were coerced because of medical debt. Now it's a he-said-she-said story, not that the land was sold but about the unverifiable nature of the tribal status of who sold it, and if that was a valid transaction. Because these homes are a strip alongside the reservation, the tribe then moves to cut water to the disputed land in retaliation. Without access to the outside utilities, the hope is to makes the land worthless to the developer and they can then buy it back to develop themselves and profit, but the developers sue and win the case after many years in the WA courts.

"As Leroy Deardorff, a Lummi natural resources officer, puts it: 'There are big bucks to be made out here.'"

Lummi nation passes around the tale of these orphans. In today's telling, they were murdered by white people! It's suspect that this particular tale doesn't appear to be told until the development dispute happened. Now salty chiefs wander reddit to tell the tale of evil white people stealing land, which is somewhat true in the long run, but the specifics of it change over time and 'white' just means anyone non-native. At this point Lummi nation identifies as 40% white, but those clinging most strongly to that heritage see anyone outside of reservation land as an oppressor and to blame for the theft of native lands and their modern problems. But mostly money.

You can read a 20-year-old telling of it here: https://www.washingtonpost.com/archive/politics/1996/06/10/a-battle-of-rights-on-the-reservation/166b7f7e-e86f-4dcd-92e9-dc76b615757d/

This person doesn’t understand why history is important to remember. That’s a problem.