I think it's interesting that you have so many responses to your comment and none of them propose that possibility. Yes, there are corrupt prosecutors, or prosecutors who just don't care. But I think most of them do care, and think they're doing the right thing. The police won't arrest you unless they think you're probably guilty. The prosecutor won't go after you unless they think you're probably guilty. The evidence points in that direction, or else they wouldn't get far. You may be innocent, but they're not working on that angle. From where they sit, you look guilty, and things like exonerating evidence will be seen through that lens, as a way for a guilty person to go free, not a way for an innocent person to avoid punishment for a crime he didn't commit.
This is simultaneously reassuring (these are regular, good people) and terrifying (how do you fix the system then?).
That's the whole point of the system. Prosecutors are supposed to prosecute those they believe are guilty (of course that doesn't mean negligently or willfully ignoring evidence that points toward innocence). While the system is supposed to presume innocence until proven guilty, it's the job of the prosecutor to prove guilt.
I think it's interesting that you have so many responses to your comment and none of them propose that possibility. Yes, there are corrupt prosecutors, or prosecutors who just don't care. But I think most of them do care, and think they're doing the right thing. The police won't arrest you unless they think you're probably guilty. The prosecutor won't go after you unless they think you're probably guilty. The evidence points in that direction, or else they wouldn't get far. You may be innocent, but they're not working on that angle. From where they sit, you look guilty, and things like exonerating evidence will be seen through that lens, as a way for a guilty person to go free, not a way for an innocent person to avoid punishment for a crime he didn't commit.
This is simultaneously reassuring (these are regular, good people) and terrifying (how do you fix the system then?).