Superficially I have to agree with you that I look like a hypocrite.
The government is the body which has a monopoly on violence. In other words, they're the only people who can legally do things to people that nobody would volunteer to have done to them, like going to prison. It's the government's job to provide courts through which disputes can be resolved, since you aren't supposed to take matters into your own hands. One class of those disputes is the government vs citizens who have violated the government's rules or the laws.
When those kinds of cases are going through the courts the government should be extra careful to be impartial because everyone can tell that it's potentially a situation ripe for corruption. The government is adjudicating a case between the government (the DA or prosecutor) and someone not in the government ("normal people").
Given the choice you wouldn't choose your wife's parents to settle a dispute between you and your wife; but this can be a very real fear when being prosecuted.
The problem here is even though you can name the different parts of the government and call them separate (courts, prosecutor, forensics, etc) ultimately we find out that forensics and the prosecutor are both "on the same team" and that when the courts get involved again to try and fix the mess, that the forensics person is still "on the same team" as the prosecutors and maybe everyone else.
If you're in the class of people called "the government" you have to be extra right, extra careful, and extra following-the-rules so that ordinary people get a fair shake when dealing with an entity that has virtually limitless funds to prosecute versus their usually meager funds to defend (unless you're in the top 1% to 0.1% or so, then it's just "lots more" rather than "infinitely more").
Here's a case where not only was the forensics person not extra careful, right and proper, not even sloppy and foolish but malicious. And not just a little bit either, she didn't tamper with one case that involved a cheating ex or something. She did it systematically over thousands of cases depriving people of their liberty wrongly. You could build a strong case that she perverted justice in a very horrific manner.
If you add up all the person-years of people's lives that she conspired to help imprison and divide by 100 year in a life (round numbers) you'd get to the point where she's effectively "taken" tens if not hundreds of lives. That makes her in a roundabout way something akin to a very impressive mass murderer. In that case I'm not sure that the death penalty is an over-reactionary knee-jerk kind of punishment.