This calls to mind complaints from a few years ago about fact-checking as "damaging to the reputation" of the person whose claims were fact-checked and identified as false.
One's reputation is damaged when they choose to tell a lie, not when someone else points it out.
Similarly, when someone accepts a bribe, they have damaged their integrity. That damage was not done by the person who exposes the bribe, but by the person who chose to accept the bribe.
Put another way: unethical behavior is unethical regardless of whether one gets caught while engaging in it.
One's reputation is damaged when they choose to tell a lie, not when someone else points it out.
Similarly, when someone accepts a bribe, they have damaged their integrity. That damage was not done by the person who exposes the bribe, but by the person who chose to accept the bribe.
Put another way: unethical behavior is unethical regardless of whether one gets caught while engaging in it.