Don't make excuses for poor writing by trying to shoehorn theories into explaining away a very obvious deus-ex-machina. While plausible, this ultimately has no more value than the indoctrination theory did for the ending of Mass Effect 3. These exercises fall on their face for a simple reason: Occam's razor.

Which is more likely? That the writers very subtly introduced a few elements that mean that deus ex machina is actually a carefully crafted plot device and sufficient foreshadowing that the writers neglected to ever confirm or that it was just a poorly-executed deus-ex-machina to dig the writers out of a dead end in the story? If this was the intended interpretation, I imagine that it would have been exposed more explicitly after the fact beyond "We controlled hatred with the power of loooooooooove."

Basically, I do not believe that the writers were so good that they intended something so subtle when there is plenty of evidence contrary to them being capable of it.