How I read the stimulus was: say we let Q be the statement "create virtuous people"
Glen: I believe Q is most important because P (an alternative) is not desirable
Sara: But Q is more dangerous than P
I can't seem to get past why answer choice C is wrong. Glen's closing sentence states he endorses law's primary role to create virtuous citizens implying there is negligible danger in making Q the most important. On the other hand Sara counters by saying this is more dangerous than being overprotective of individual rights, thereby implying she believes there is an inherent danger in the government deciding what constitutes virtuous behavior. Wouldn't this point be something they directly disagree about?
So E summarizes Glen's argument, but Sara simply disagrees by stating Q is more dangerous than an alternative and seems to imply Q may not be the most important. But I feel that the level of interpolation to go from Sara's argument (Q being more dangerous) to Sara believing Q is not the most important is the same as that for C.
http://classic.7sage.com/lsat_explanations/lsat-56-section-2-question-17/