Comment by NoGravitas

Epicureanism was fairly heterodox/countercultural even during its heyday, and our sources on it are much more limited than the sources on more acceptable schools such as Stoicism. For example, we don't really have any writings from Epicurus except for short fragments, when we know from his students that he wrote many books. Much more survives from his students, but even then one of the main sources of our knowledge of Epicureanism (especially before we started recovering Herculaneum scrolls) was Seneca, a Stoic writing about it as a rival school. None of this was forbidden at the time, but it was unpopular (especially among the ruling class) and eccentric (ditto).