I've seen a possible choice when everyone starts considering IAOS as a culprit. It goes like this: "IAOS isn’t a culprit. Why are we even considering them?" How do you unlock it?
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So if you see any locked choices, that's because up to that point you might've been choosing options that, in this case, made you seem skeptical of IAOS. So if you don't have enough brownie points for loving IAOS it doesn't add up and those choices get locked. Basically, if your past acitvity/choices don't match a certain choice it isn't available.