Whether you believe it or not, the DNC has put the thumbs on the scales before, they're doing it now and a part of that is the debate criteria and how which polls count and others don't. You're looking at it as tho "oh this poll is not qualifying for everyone, so how is it targeting tulsi" and not at the why is this poll not qualifying considering all of the facts of this poll? On top of that why are they so hush hush about it?
But that's not the same thing as saying the DNC is out to get Gabbard which is the narrative that's been pushed by her campaign and many supporters for months now.
Is it odd they don't count that as a qualifying poll? Sure. Did they intentionally leave out that poll for the purpose of harming Gabbard's election? No.