Hi, Jude!
Great questions!
Passage B's author intellectually agrees with A's premises about how we might not actually have free will because of biology, and thus sympathizes with A's premises. So in respect to the first half of choices A and B, they seemed interchangeable.
They are not quite interchangeable. "Sympathy" implies that the author is ethically disposed to favor the implications of these premises. "Intellectual acceptance" only indicates that the author accedes to their validity without any ethical judgment.
The second half of the choices threw me off because I found (what I thought was) textual evidence for both. Passage B is clearly doubtful about the feasibility of removing culpability from the justice system, but the last paragraph of Passage B made me think the author was even more concerned about the consequences of removing culpability if it were possible.
There is no relative degree of concern implied in the passage. Further, there is nothing to suggest that this concern amounts to "fear."
I interpreted this quotation as saying that removing blame from the justice system won't be harmless, i.e. could have consequences.
You're right that according to the author "removing blame" cannot be assumed to be "harmless." While the author assents that blame may have a social function, there is no indication that the author dreads the idea of "removing blame." Instead the author proceeds from an understanding that removing blame is simply inconsistent with social realities (c.f. end of paragraph 3, passage B).
Also, I can't see why the author would even address the potential harms of removing culpability unless they thought it was at least somewhat feasible. In other words, by recognizing that the justice system can confront the issue of free will/biology/blameworthiness, the author is acknowledging that tackling that issue within the system could happen to some degree, on some level.
In fact, in paragraph 3, the author of passage B states that a rehabilitative approach was attempted. There was no "harm" here. The response to the rehabilitative approach was a "retributive backlash." In other words, the "harm" came from the proclivity of people to blame!
At a more basic level, and more important, focus on answer choice (B) in much more simple terms.
First, what do we mean by "if such acceptance becomes widespread?" This means "acceptance of a system of a non-retributive criminal justice becomes widespread."
Would the author "fear the consequences" of widespread acceptance of a non-retributive approach to criminal justice?
No, there is no support for the idea of fear. Instead the author simply points to historical example to suggest that such reforms are not-feasible. According the the author, they're not feasible now because they already weren't feasible fifty years ago.
The final paragraph is a discussion of this reality, this blame-filled social reality that presently exists. The author exhorts the reader to understand this blame, whence it arises, the function it serves.
I hope this helps!