Final answer:
Allan's use of the word 'slaughtered' exemplifies a critical attitude toward the harsh repression of peaceful protest in the People's Republic of China, contrasting it with the US Supreme Court's protection of symbolic speech like flag burning.
Step-by-step explanation:
Comparing the use of the word "slaughtered" instead of "killed" indicates Allan's critical attitude towards the subject matter. The term "slaughtered" suggests a brutal and inhumane action, one that is deeply negative and indicative of Allan's disapproval or condemnation of the event in the People's Republic of China. In contrast, the term "killed" is more neutral and would convey less of the emotion and critical judgement that "slaughtered" does. The way Allan presents these two events reflects his perspective on the right to express disagreement with government policies, juxtaposing the Supreme Court's protection of symbolic speech, like flag burning, with a government's harsh repression of peaceful protest.