What the OP says IS NOT TRUE. The authors he cites are NOT the authors and not even autorities in Kabbalah but XIXth century occultists who tried to use it for their own purposes and in their own way.

Kabbalah is NOT based on the Zohar. The Zohar, being an exteriorization, is based on and is a subset of Kabbalah. Kabbalah existed long before the Zohar surfaced.

The OP is either misisformed or has an ideological agenda to pass (probably both).

Even the New Testament (B'rit Hadashah) states in several passages that Jesus (Yeshua) said some things to his disciples only in private.

What are these people like the OP afraid of? Of being excluded from the knowledge of the One and His action through the Universe? Perhaps they have motives to be afraid...