"We can't not have police, this will lead to a slippery slope that will lead to Mad Max anarchy and roaming bands of killers and warlords riding in really awesome-looking semis."

That's the entire problem with the slippery slope! Two entirely conflicting, equally compelling arguments can be construed with it, starting from the same simple question - "Should there be police? Yes/No?"

Just because the bottom of a slippery slope looks awful, or can't be seen isn't a reason to do, or not do something - because I can construct a million awful slippery slopes for any action you do, or not do.

A slippery slope argument eliminates all nuance from a question, and provides no guidance for answering it well. That's exactly what makes it a logical fallacy.