In order to establish a set of norms in a community, it's not enough to punish people who violate the norms; you need to punish people who don't punish people who violate the norms. In other words, you need to watch the watchers.
To reframe that principle in this context, it's not enough to punish people who ask for bribes. You need to punish people who answer those asks, rather than reporting them.
What we really want is to create incentives against corruption. If a public servant asks you for a bribe, it should be legal to pay it. You are then in the clear to turn around and report them. But making both parties equally guilty leads to the initiator having power over the other. When that happens, neither want to disclose except as part of mutual assured destruction.
To reframe that principle in this context, it's not enough to punish people who ask for bribes. You need to punish people who answer those asks, rather than reporting them.