Baffling only if you don't think about it.

The police make a deal with some murderer, get their information, and then go back on the deal.

Then they do it again.

Then no one ever cooperates with the police again. Plea bargaining is no longer a thing. Every criminal case goes to trial.

Right now, over 90% of cases in the US are settled with plea bargaining. That number is obscenely high. and this needs fixing, but under your plan, those would all go away.

Suddenly the courts are overwhelmed with ten times as many trials.

Don't get me wrong - it's obscene that this guy gets twenty years whereas there are people serving life sentences for nonviolent cannabis crimes. The issue is that the system doesn't have the resources because it's overwhelmed with people who shouldn't be in jail in the first place.

But you won't fix that by getting rid of plea bargaining!