I agree with this.
I'm sure they've considered the most direct effects of the great attractor. My concern here is that the effects are so tiny, so confirmation bias becomes a big factor.Isn't it possible that dark flow is just an illusion caused by the great attractor itself? It could be that photons from the CMB are slightly pulled toward the great attractor as they approach our telescopes. That would also cause the effect to appear in the same direction. It could be that the Planck team factored that out and the WMAP team didn't.