Most of the legal gambling in the US, other than in Nevada and Atlantic City where they just didn't have much else to offer and actually got to vote on it, is sort of an accident resulting from the argument that the "tribes" retained some sovereign authority over their own people, and hence, in some cases, were exempt from local, state, and even US laws that prevented anyone else from legally starting up a floating crap game.
The simple fact that most gambling centers are "Indian casinos" (the term commonly used here) is just due to that "loophole" being apparently available only to the tribes, so anyone wanting to run gambling has had to create and maintain at least the appearance that "there's injuns" in control. Whether there's really anything "Indian" about those who actually control the gambling now is, in many cases, questionable, and whether most of the "profits" go where they're nominally supposed to, or go elsewhere, is something few Native Americans could tell you, even if they're involved in operating the casinos.
Calling them that is just a shorthand for "gambling places operating under 'the usual' special rules." It says nothing about any "value judgement" about Native Americans, or tribal law, culture, or custom, about how well their neighbors get along with them, and especially nothing in particular - at this point - about who's pocketing most of the profits.
All that is known, IMO pretty clearly, is that that money is what's doing the talking to/for those who "administer" the laws on gambling - locally, in the state legislatures, and in the US Executive, with respect to local/internet/international or other kinds of gambling.