While listening to negative information for constructive purposes is not a violation of the prohibition against accepting loshon hora, before taking the liberty of listening to such information one must be sure that he will not be guilty of causing the speaker to sin.
We have seen that in order to convey pertinent information that would otherwise be considered loshon hora several conditions must be met. For example, the speaker’s intent must be to bring about a positive result. If the speaker does not have constructive intent, his words are loshon hora, despite the fact that the information is important for the listener to hear. In such a case, being a listener would be a transgression of “Before a blind person do not place a stumbling block” (Vayikra 19:14).
If one is privately doing business with someone and then, by coincidence, a friend begins speaking loshon hora about that very individual, one is required to interrupt him or walk away! Since the speaker is unaware that the listener is doing business with this person, the speaker is talking loshon hora and must be stopped. After interrupting him, one may tell him that the information he had begun to relate may be important to the listener, and that he may continue speaking provided that he can honestly relate it for that constructive purpose.