When most people advocate for divesting, defunding, or abolishing the police, they aren't suggesting that we go without literally any law enforcement. They simply believe the current system is too broken and corrupt to be reformed and that we need to start completely over. These advocates are generally against other avenues of reforms because those reforms can give a false sense of accomplishment without addressing the underlying problem. Reform or any level of support for the current police system in the US is therefore seen as delaying that ultimate end goal of having a just law enforcement system in place.

To put it into computer terms, it is the equivalent of your computer performance degrading over time. You can try force closing programs, restarting the computer, removing programs from autorunning at startup, updating drivers, uninstalling unused programs, etc. However sometimes none of that will truly work and you will need to reinstall the OS.