With no confirmed film, show or creator source attached to this clip, its popularity comes entirely from how useful the single word is online. Short word soundboards spread because one loaded legal term can do all the joke on its own, and defamation fits arguments, callout posts and parody legal threats perfectly. Creators reuse it as a reaction button whenever someone overstates a claim or invents a story, letting the formal language undercut the silliness of the situation without needing any extra context or explanation.