It seems to me the truth of corruption versus petition is if the politician sells their vote for cash or actually listens to the merits and makes a decision.
Now that is hard to judge from the outside, but that is the real difference.
I suspect many people believe those in power now are mostly selling their vote for cash not making decisions based on the merit and just happening to side with those giving piles of cash because they heard those people give explanations of why favoring them was a good move for the country.
A few years later it is often not. But politicians can lie legally even if uncovered and documented in lengths afterwards. Funny fact: German president Horst Köhler had to resign from office for saying the truth.
Now that is hard to judge from the outside, but that is the real difference.
I suspect many people believe those in power now are mostly selling their vote for cash not making decisions based on the merit and just happening to side with those giving piles of cash because they heard those people give explanations of why favoring them was a good move for the country.