Q: Why must we insist that black lives matter ?
A: Because the US Constitution states that black lives are only equal to 3/5 of a human being
From its inception, the United States has been committed to the abhorrent idea that white lives matter and black lives do not. This perversion of democracy has been perpetrated in part by the Three-Fifths Compromise.
Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.
(Article I, Section 2, Clause 3 of the US Constitution .)
The Three-Fifths Compromise explicitly states that there are two kinds of people in the USA: Real Men and Others. Consequently, the US has always treated white men as first class citizens, and it has always treated people of color as subhumans. Many privileged white Americans dispute the idea that the Three-Fifths Compromise has played such an important role in cultivating an unremitting culture of violence against people of color.
Though privileged white Americans prefer not to see it this way, the Three-Fifths Compromise constitutes a declaration of war against people of color. The Three-Fifths Compromise asserted that "Indians" were essentially political non-entities. As such, the Three-Fifths Compromise enabled the US government to carry out continent-wide genocide against America's Indigenous Peoples without the slightest moral qualms. In addition, the Three-Fifths Compromise made African American slavery an integral component of the American polity until 1865. Though the Thirteenth Amendment abolished slavery, the Three-Fifths Compromise has remained an integral component of the US Constitution and has continued validating horrific violence against people of color to the present day.
The Three-Fifths Compromise continues to assert that there are two kinds of people in the USA: Real Men and Others. With that very persuasive suggestion planted deep inside the American psyche the US continues to treat people of color as if they are deviant subhumans. That is why it is so dangerous for people of color "to be black in public." That is also why people of color are vastly overrepresented in the criminal justice system, and that is why people of color are so routinely murdered in the streets of America.
As long as the Three-Fifths Compromise remains an operative, highly visible component in the USA's most sacred document, the US will continue treating people of color as if they are wartime enemies.
Integral as racism has been in US democracy -- and difficult as it may be to believe -- it is possible to eradicate racism. The key to eradicating racism in the USA is to officially terminate hostilities against people of color in much the same way that the US has terminated hostilities against wartime enemies. After D-Day heroes murdered Germans, after VE Day only murderers murdered Germans.
In order to eradicate racism, the USA will have to change the policies which state that people of color are subhumans -- and the USA can, therefore, treat people of color like wartime enemies. In conclusion, the USA needs the Black Lives Matter movement in order to transform the USA from a racist dystopia into the democracy that it has always falsely claimed to be.