If you can’t trust your police with it, then there is something fundamentally wrong with your society.
This announcement coincides with protests against police brutality, at which many police have behaved brutally. That was sparked by an outright homicide by a police officer, captured on video, of a man who was subdued and presented no threat -- while other police officers watched, and many others have subsequently attempted to justify.
The "something fundamentally wrong" is very complex and subject to genuine debate, but it's not subject to debate that whatever it is, people don't trust the police.
Isn't "defund the police" 99% "that's a nice slogan", not actually "we'll be good without any form of law enforcement"? From what I understand it's a play to break unions: you defund and dismantle the police department and then you can create a new department, can start fresh with new people, new tactics etc pp. Might work, might not, but it's certainly not "eliminate policing".
you can google for more details.