Because in both texts the author uses two viewpoints in which they justify in what the see in the same event which was the Boston tea party, the Tories believe that the Sons of Liberty are a bunch of brutes and are violent for what they do, or what they see in that exact event. And meanwhile the Sons of Liberty explain they viewpoint during that same event telling the reader how they feel about the taxes.
In the passage, the speaker makes direct reference to (her) face being like a mirror, reflecting how he felt and showing his own expressions and thoughts.
