en.wikipedia.org/wiki/Libelle_(literary_genre)

French reference dictionaries define libelliste as the person who writes libelles, not the publisher.

• The CNRTL/TLFi entry states: "Libelliste, subst. Personne qui écrit des libelles."
• Le Robert likewise defines libelliste as "Auteur de libelles."

So the article’s wording is inaccurate: a libelliste is an author/libeler/pamphleteer, whereas a publisher would be an éditeur, imprimeur, or libraire depending on role.

The word "invariably" is too strong here. Scholarly work on libelles shows that they were used not only for political attacks, but also in literary quarrels and against writers.

Evidence:

1. Jean-Alexandre Perras’s article on Simon Linguet studies libelles specifically "dans ... sa querelle littéraire avec André Morellet" and says the category of libelle was used in "querelles (judiciaires ou littéraires)". That is direct evidence of libelles in a literary, not purely political, setting.

2. Stéphanie Gehanne Gavoty’s study of Grimm’s Correspondance littéraire identifies several libelles against Jean-Jacques Rousseau and notes that the targets of libelles included not just political figures but also writers. The article explicitly says: "Les nouvelles figures publiques que sont les écrivains s’adjoignent aux figures politiques ..."

Because reliable scholarship documents libelles in literary and personal polemics, the blanket claim that they were invariably political is incorrect.