The inverse of immunity is not that any prosecutor can prosecute. That's the happy medium. Even the most reckless prosecutor would still have to convince a jury

The inverse of immunity is not that any prosecutor can prosecute. That's the happy medium. Even the most reckless prosecutor would still have to convince a jury, and would still have to go up against a defense in court. The inverse of total immunity (freedom, no jury, no trial) would be total oppression (prison, no jury, no trial).