Maybe that is their ultimate goal - nobody call 911, because there will no longer be a police force.
No police protection for white people.
It depends on who "they" are.
Look at Chicago. If "they" is leftists and BLM/Obama agitators, what you say is correct. They'd like to empty the prisons, too, for a while. Criminal auxiliaries are a staple of insurgent revolutionaries who want to destroy all order before they take over. USSR, the Balkans, certainly the Nazis... all had undisciplined criminal paramilitaries terrorizing scapegoated groups as well as the general law-abiding population.
If "they" is law-abiding black Chicagoans, I'd say no. They're tired of being shot by the dozens every weekend. But, they're also cowed by the noisy leftists, as well as suspicious of the police--a good portion by propaganda, some by experience. They'd prefer to live safe lives.