They exist to prevent crime and to catch criminals.

They really really don’t, never have done.

Nobody suffers more at the hands of crime than the working class.

Why do you think that is? There’s a reason cops are called class traitors

The rich are safe and sound in their gated communities and penthouses with private security.

Right, and the police is the private security of the state, there to defend it and its interests (and those of the rich who actually call the shots, it isn’t private police arresting anti-oil protestors, in defence of the interests of the oil industry for example), not you and yours.