When you dig back to the probable origin of this story it occurs when the monotheistic Hebrews were in direct competition with other local religions, some also monotheistic, some polytheistic, and many matriarchal in religion & social structure. In the oldest available Judaic texts the tree seems to be a species of Fig that was regarded as sacred by a number of the matriarchal religions/societies. The Asp snake was also deeply connected to these matriarchal religions. In that context the story can be interpreted as a priestess or practitioner of a matriarchal religion 'corrupting' a otherwise innocent Hebrew male with her religions practice. There is also some evidence Hebrew women were for a time following the rites of a matriarchal religion in parallel to the patriarchal practices of the Judaic religion. The story may derive from a effort by the priests to wrest full control for either religious practice, or a economic control, or a political dispute. Probably a combination of the three, these things seldom are one simple cause in isolation. I've seen interpretations of the Biblical book The Song of Deborah as a remnant of this matriarchal aspect of Hebrew religion.