It's more of a case of the boy who cried wolf than it is of denial.

Too many people see something they don't like, imply a nefarious motivation without evidence, then expect everyone to agree that it is corruption.

If there is corruption, show the evidence. Otherwise, be honest and state that you don't agree with something. If you want to persuade people, back up your claims with verifiable evidence without falling back to nebulous claims of corruption.