I think for many there has always been an assumption of this. Saudi Arabia has funneled money in the past to terrorist organizations opposed to Israel and the West.
Except that Israel despite being a logical target has mysteriously avoided terror attacks from Al-Qaeda or ISIS.
Of course, why SA would think that terrorism will keep the US out of the Middle East, that's the missing piece of this picture and may invalidate it.
The answer to both of your questions is Iran. Which makes Israel and ISIS strange bedfellows, when Israeli fighter jets dropped bombs on Iranian-backed militas fighting ISIS in Syria.
This is the current prime minister:
https://en.wikipedia.org/wiki/Naftali_Bennett
Although the background isn't that much different from Netanyahu.