You apparently have no actually understanding of the criminal justice system.
Until charged, the government has no responsibility to provide anything.
Once charges are filed, the Prosecution has a duty to provide all potential exculpatory evidence. However the rules of evidence and witnesses in criminal procedure are different than in civil cases, which usually are governed by detailed discovery rules.
Calling me a Nazi because I have a minimum understanding of the criminal justice is both infantile and asinine. This is how it works, and its the one you always derp derp supporting when its Joe Shmo being prosecuted.
Do I agree with it? No, its designed to railroad Da Poorz and Da Middle Class. But thats what it is.