Yes, they support themselves via non-tribal customers. But their land claim was dismissed because the feds did not join their lawsuit and the State declared sovereign immunity because the State is the sovereign, NOT the tribe. Their latest plea was to the UN, which does NOT trump the US Constitution.
As a signatory to the UN charter, any treaty laws recognized under UN law, are indeed equally as binding as the US Constitution. The same applies to ALL US treaties.
Everyone's entitled to their own opinions, but not their own facts.