People cannot be morally responsible for things over which they have no control.
Claims
conditional (cannot be X for things like Y)
Have no control → can't be morally resp.
conditional (any)
inevitable conseq → can't be morally resp. of uncontrollable thing
wishy-washy application of 1st rule
It's hard to know whether adults have control over how they're treated, and thus it's hard to know whether they bear responsibility for how they're treated.
strong statement (everyone) / pivot (however)
We all sometimes act in ways that are an inevitable consequence of how we were treated as an infant.
Infants cannot control, and so are not morally responsible for the treatment they receive.
Evaluate
It's a safe bet that the 3rd and 4th sentences are just filler. We're doing a Must Be True question and these claims are nebulous: "it's hard to say".
Meanwhile, it's very typical for Must Be True to test our ability to combine early and late ideas, with the filler in the middle being the way they distract us.
We're keenly attuned to Overlapping Language on Inference questions, and the last couple ideas about infancy are invoking language used in the rules of the first two sentences.
Everyone sometimes acts in ways that are an inevitable consequence of treatment received as an infant. According to rule 2, we're not supposed to be held morally responsible for any inevitable consequences of things over which we have no control.
Can we apply rule 2 then? Is the "treatment received as an infant" a "thing over which we have no control"?
Yes, we are told in the final two claims that infants clearly cannot control the treatment they receive.
Goal
So if we apply rule 2 to the claim that , then we can say that .