Query about Question 13 from "(GRE Big Book) Test 5 Text Completion Problems (14)" [9760]

https://www.gregmat.com/quizzes/quiz/gre-big-book-test-5-text-completion-problems-14 (Question 13)

For this question, I personally do not understand why there can’t be two sets of answers here:
1 exceptionalism…unlikely (associated with histrionics/unlikely)

2 mediocrity….eager (associated with mediocrity/desperate)

I ultimately chose histrionics/unlikely because I understood the “make their ready ovations meaningless” to mean that audiences should NOT want to make their ovations meaningless. I’ve seen the other discussion post regarding this, but that reasoning still isn’t clear to me.

Question: I understand how to get the correct answer, I’m asking how do I conclude that the histrionics/unlikely answer choice is wrong?

Thank you!

Ready ovations = eager to be pleased = likely to be pleased ≠ unlikely to be pleased