It often happens on social media: you point out the devastating human cost of a policy that’s popular in some quarters. The response—whether from a troll army or from a leading propagandist—comes fast.

When that happens, remember: the responders aren’t talking to you. They’re not trying to convince you of anything.

The audience is readers on their own side. More specifically, any readers on their side who might feel a pang of conscience. Thousands of innocent people locked away? Small children expelled to countries where they’ll be vulnerable orphans? The steady advance of de-democratization?

That sort of thing, when you point it out, may make at least some of these policies’ and leaders’ supporters feel queasy. Your message may plant a seed of doubt with some of them.

The job of the troll and the propagandist is to dig up that seed and destroy it. To find a rationalization, however false, that eases the pain bubbling up in some followers’ conscience. Making the voice of doubt appear ridiculous, so that everyone on “their side” stays in line.

The job of the troll and the propagandist is not to debate you. You are not the audience. So don’t bother engaging them.