Reb Eizana, are you talking about in his dictionary or any of his other accomplishments? I did see very Apikursive stuff from him, though not in his dictionary. I don’t use his dictionary anymore anyhow, as per advice of an Adam Gadol.
The Gemara describes how Reb Eliezer was punished for enjoying a ‘good Vort’ from an Apikoros. One may ask, what should he do if it’s true? The answer is as it says, V’shem Reshaim Yirkav, that we don’t give the unworthy a place in Torah. There has to be a special Zchus to have been Mechaven to Amita Shel Torah. Do’eg and Achitofal were very learned, and yet it says of them (Sanhedrin 106b) that they were not worthy to achieve the Halacha in their learning, as it says Sod Hashem Lirei’av.
There is a Tosafos that changes a Girsa based on this. The Gemara has a Rasha asking a Shaala and Tosafos says that it must be a mistake, since we don’t give such a person a place in the Torah — even as the one posing a question.
That’s why.