There's either a "we" ("I + you + them") or there isn't a "we"--just an "I"). What the individual is trying to say is "I am not like them." But it's not enough just to maintain that "I haven't shot black people in a grocery store."

If the "I" doesn't want the "we" to include murderous racists et al., then the "I" has to work to eliminate murderous racism from the "you / them"). And this elimination necessitates years of hard, dedicated work--starting with various systems that cloak murderous racism (education, religion, politics, etc.). If someone admits that "This IS us," then that individual has a chance to change the world so that one day it won't be "us."