Certainly true, and hits close to home. I am not actually working as an attorney right now, but in a similar field in a bureaucracy. For all the ire attorneys get, at least they tend to be halfway informed about how things function and how to win. There's nothing scarier than people who have no idea what they are doing making decisions, well-intentioned or not. And then doing the same thing over and over again expecting a different result.
And I am very aware that some balances are "dishonest", or at least that they are certainly imperfect. Unfortunately there is no perfect system. I definitely am one for finding out the truth and being suspicious of anything that does not look right - it's rare anyone has the authority to do much about it, though, unfortunately, and it's hard to come up with a better system than the flawed one we have IMO. But I am definitely aware. In fact, one of the things that recently came up in my bureaucracy that was driving me crazy was those around me kept asking "what happens if quality control doesn't do what it is supposed to do? who is watching them?" They were very worked up, but I mean, the buck has to stop somewhere. It doesn't go all the way to God. We can only have so many checks in place. If every one of them comes to the wrong answer, hopefully that is rare but it is unavoidable. If every one of them is corrupt, then I'd say it's likely we the public did something wrong if that's the government culture.
And in this type of case, the checks/balances thing doesn't really go both ways. Had an erroneous indictment been brought, hopefully at some point they would have been exonerated. Where charges that may have been warranted were not brought, there's not much of a check/balance. That is discretionary for a reason. The system guarantees people certain rights if they are going to be criminally charged. There is no right to having a case prosecuted. That's kind of the antithesis of our legal system - the burden is on the state for a reason. A prosecutor can be morally wrong, but not overruled on a discretionary matter.