Because I was taking the thrust of his position as you stated to be applicable to Epicurus' school as well as other ones.
The thrust of Lucian / Lycinus' position is applicable to all schools. including Epicurus' school, because it's not a denunciation of all knowledge. It's a test of knowledge that applies to any school. I would say and I would argue Lucian saw too that Epicurus' is the only school that passes the test as given in Hermotimus.
The entire point of Hermotimus is to demolish ideas such as (1) that the you should devote your life to doggedly pursue virtue, in essence climbing and fighting your way to the top of a mountain on the idea that being at the top for only a moment is worth a lifetime's struggle, or (2) the goal of life is some mysterious abstraction that you need a guru of logic to haul you up as with a rope because you can't do it yourself.
Both of those points being attacked are not just inherent in Stoicism, they are inherent in Socrates, Plato, and Aristotle as well. But they are not inherent in Epicurus, who holds that both are ridiculous.
So Hermotimus is by no means limited to attacking Stoicism. Epicurean philosophy is by its very nature an attack on Stoicism / Platonism / Aristotelianism and all "otherworldy" claims.