These questions usually trip me up, so I will give my thoughts on the answer choices and what I believe the takeaway is.
Type: Purpose/Author Viewpoint
Method: Visit each word in the paragraph and ask 1) "Is this referring to "the reasoning offered in the U.S. Supreme Court's decision in Shelley v. Kraemer"; and 2) "Does it reflect the author's 'attitude,' i.e. tone?"
A) This refers to the "ruling," not reasoning. Eliminate.
B) "Justly celebrated" refers to the "decision," not reasoning. Eliminate.
C) "Perfectly legal" refers to the covenants, not the reasoning. Eliminate.
D) "Consistently applied" refers to the approach, and while this could refer the reasoning,
it is too neutral for the passage as a whole when you consider that the passage is all about
criticizing Shelley v. Kraemer. Eliminate.
E) "Noxious aspect": That whole last paragraph addresses a issue that the author takes issue with, that
the court did not condemn the prejudices involved in the case which led to a roundabout solution
that eventually became a problem as well. Correct.
Takeaway: For these question types go one-by-one and make sure that the quoted language in the answer choice is
1) addressing the issue in the question stem, and 2) is textually correct.