It is frequently advantageous to stop communicating with someone, whether as social punishment, avoidance of feelings of awkwardness, or to dissociate yourself from low-status friends. People want these social advantages, but many people prefer not to undergo a "breaking-up" conversation, even when in a non-romantic context. (For obvious reasons: it's likely to be a conflict-ridden conversation, and their motivations often do not sound noble when explicitly stated.)

Dropping that person like a hot potato is a way to get the social win without the corresponding awkwardness.