That's because those in power are the moderate ones, who are able to keep the most extreme elements of Islamic fundamentalism at bay. You want to topple Saudi Arabia and UAE? Great, now it's run by ISIS. Sometimes you have to choose the lesser evil.
This geopolitical calculus might have made sense when there was a real danger of such countries being swallowed up into the Soviet Union’s sphere of influence. But it would be much better now to disengage as much as possible with the governments of countries like Saudi Arabia and the UAE.
They won't have as much luck with Iran, since it's government is so strongly aligned with the fundamentalists, the pool of willing cannon fodder will be smaller.
I hope, at some point, these illegal regime change operations that the US and other western countries have been involved in for so many decades, will eventually stop.
Also, when chaos is set into motion, the west has to decide if the costs of not getting involved are greater than getting involved. Often doing nothing isn’t viable either.