When the baseline of corruption is high enough and those who judge you are equally or more corrupt, convictions for "corruption" are a weapon from those who do not want a specific someone on the government rather than real intention of reducing corruption.
Simplifying, it's like this: If the road to presidency is corrupt, you either become also corrupt (on a varying degree) or stay as one of those parties with no more than 1% of the votes. But then, there's a pact of silence between cronies. And those who are accused of corruption are the ones that either went too far or went against powerful people in the government.
This reminds me of why I hate when government agencies excuse an overly broad rule by saying they "won't prioritize enforcement" against favored/minor actors. Eg [1].
Simplifying, it's like this: If the road to presidency is corrupt, you either become also corrupt (on a varying degree) or stay as one of those parties with no more than 1% of the votes. But then, there's a pact of silence between cronies. And those who are accused of corruption are the ones that either went too far or went against powerful people in the government.
I take all those trials with a grain of salt.