Yeah i used to believe that cops are here to protect us (working people). Then growing up I learned that if you don't have the money or power, never deal with cops (other than license and registration shit). I understand why my late grandma forbade all her kids to marry cops.
Nope. Even in a hypothetical world where all the ones guilty of a sufficiently severe crime and ONLY those go to prison, that doesn't make the world a safer place with less crime.
Punishment and the fear of same isn't anywhere near as powerful a motivator to stop breaking the law or deterrent as they've been telling you.
If it was, the US would be by far the safest with the least crime of all Western countries in stead of closer to the opposite.