I supported NoDAPL because I (almost) always support autochthonous peoples in any dispute against governments or industries (at least in the US, where I am better informed regarding the historical realities); and, furthermore, because I am against the continued scaling-up of fossil-fuel usage. There are some other factors, as well; but how's that for an "actual answer"?
At least someone did.
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As for Manning,
she had already been jailed for longer than any other individual had for a similar crime in United States history—mostly under the inhumane conditions of solitary confinement—and, moreover, a commutation only signals clemency, as opposed to a pardon (which confers the shape of approval for the act committed). She's still a criminal in the eyes of the US, she's just been granted mercy (which, as an ostensibly-Christian nation, we should always champion).