In most of human history the elites controlled information and speech.
The reason was very simple—they had the political power and wanted to keep it.
If the citizens could speak freely they might decide that the elites were exploiting them and might decide to do something about it.
The elites always fear that the people might disseminate “disinformation”—which equals any views that oppose the ruler’s narratives—and “conspiracy theories” which suggest that the few are exploiting the many.