That is an opinion, sure. Another is that you stop separating 'The StAtE' from 'The People,' because it decent societies there is no effective difference. (Actually in all societies, there is zero difference whatsoever, but we really aren't here to talk about implied consent)

The state doesn't need to be infallible, because people aren't. But we can be sure beyond a reasonable doubt. If a mayor of a province that has directly harmed hundreds of thousands of people and was found with literally 40 tons of Gold and Cash says they're innocent, they have a pretty large hill to climb. We can be reasonably sure he at least had something to do with the bribes, and we can be reasonably sure a poor student from a poor family turned extremely low level politician did not find a way to hoard 40 tons of gold and cash through legitimate means. On its face just that evidence pushes that beyond a reasonable doubt, but beyond that the offender still gets a guaranteed defense in court. The one referenced obvious lost, because of course he couldn't defend those actions or explain away 40 tons of gold and cash, but he had the chance to push some, ANY doubt into the mind of the jury.

This also isn't like the US, evidence can't be thrown out of court and doesn't have to be approved by the court; meaning any exculpatory evidence the defense can find can and does get introduced. If you're innocent and can prove it in any way, congrats. If you find a filing mistake by the People's Prosecution, congrats. If you can prove a flaw in their methodology, congrats. 'The State' doesn't set the narrative, the court only exists as a way to to guide the jury on what the law is. It has no relationship with the prosecution.

And yes, the death penalty is reserved for those that cannot be rehabilitated. A man does not come back from literally decades of taking bribes. A man cannot change that drastically overnight, it is pure naivety to think otherwise (and ignorance of psychology). The Norway style of keeping mass murderers alive forever just to... say that they didn't kill them and feel smug about it does nothing for public safety, and just costs money. All for a smug since of superiority about being kind to people that want to kill you. China was under a dictatorship less than a century ago, they had this whole big revolution about recognizing and not being kind to those people.