Cops don't enforce drug laws in particular areas because wealthy people live there and not only will arresting wealthy people and their kids get those guys a call from their boss, but the courts will never make any money off prosecuting wealthy people that can afford to drop thousands of dollars on a lawyers and the court case. Drug laws are enforced in poor areas tho because poor people can't afford good lawyers or drag the process out for years and potentially cost the court tens of thousands on just a single case, they instead get give a disinterested public defender, or maybe a bottom tier of private lawyer if they can afford it, against a prosecutor who's entire job is to ram cases and plea deals through the system as fast as possible to make a profit and fund the court and local cops. Judges that don't convict enough get the boots, prosecutors who aren't big enough dicks get the boot, public defenders that don't recommend a ton of plea deals or are too good at their job don't get offered as many public defense cases.