From a description of Miami on the Cyberpunk wiki

Naturally, these organizations were dominated by the various drug cartels. After the bioplague destroyed the drug crops in 1992, their authority faded away to nothing. One by one, the drug-producing areas of South America were destroyed. With no commercial crop to provide cheap raw materials, and no end to the drought in sight, these criminal elements began to feed off each other in a desperate attempt to monopolize the synthetic drug industry. In the beginning, violence increased nation-wide as the drug cartels beat themselves to death. But while the shooting eventually stopped in most places, it only got worse in Miami, until eventually the city was in flames. Unable to stop the warfare, the government cordoned off the area and let the combatants exhaust themselves. It was not a question of refusing to save innocent lives; most of the honest (and moneyed) people had fled Miami at the beginning of the troubles. The city had already been destroyed, and the gangs had vowed never to give up their turf.

By early 1996, the war was over; Miami was as bad a city as Beirut, a wasteland of half-demolished buildings and bullet-riddled car wrecks. Above this splendid kingdom stood the Bloods-just in time for the worst of the Collapse.

Just peak fucking liberalism, uncritical acceptance of 80s and 90s war on drugs propaganda. It's like Robocop was canon, but the writers didn't realize Robocop was a satire of America's War on Drugs politics and white media hysteria.