These people are holding signs that are general stereotypes towards their race. Whether people believe these things or not, they have a drastic impact on an individuals life. Stereotypes is an oversimplified fixed idea of an individual.
We all should know that diversity makes for a rich tapestry and we must understand that all the threads of the tapestry are equal in value no matter what their color. - Maya Angelou Quote by Nate Williams Illustration and Hand Lettering
If you don't respond to 'Blue Lives Matter' with the catchphrase 'All Lives Matter' than you clearly understand the concept, you're just choosing to cast a blind eye to the institutionalized racism in our country.
Second unfriendly reminder that not only is race a huge factor, but so is gender. The black kid may have robbed a convenience store, but the white kid *only* raped a girl. And we all know how our country views rape.