An audience can laugh together for reasons that would divide them if explained.

Shared laughter usually depends on nobody explaining it. The room is laughing at slightly different things, from different assumptions, and the unspoken quality is what lets it stay collective. Put the joke into plain statements and the differences surface immediately, sometimes uncomfortably.

This is not a reason to distrust laughter, which is one of the better things people do together. But it is worth noticing when a shared moment depends on remaining vague. In a group, in a family, in a workplace, some agreements hold only while unarticulated. Deciding when to leave those alone and when to open them is a real judgement, and both choices have costs.