Because it's in the #news lately with a couple things, in case anyone doesn't understand...
The reason why #prosecutors (and on some level #defense #lawyers) are not supposed to have ulterior motivations for or against any of the involved parties is because, while they are supposed to argue the case to the best of their ability, their primary obligation is to the #law and the #judicial process. A prosecutor is not, for example, supposed to find ways to get around the #defendent's right to defend themself, especially not by witholding evidence as the #DA did in the Rust movie set shooting accident case. Yes, there is oversight, and yes, there are consequences including being disbarred, but the first line of defense against misconduct is that lawyers are supposed to avoid getting themselves into cases where they might be tempted to break the law.
Yes, they break this all the time, but this is how it's supposed to work.
If you see something about a #prosecutor being biased against a defendent, that's why.