Islam didn't provide a template for a perfect political system. Ever since the Prophet died there was no agreed upon governing system. It was all left to agreements between consenting adults, just like any trade agreement. And the Sahaba/Caliphates no matter how holy and saintly they were, they are not the Quran, so we are not obligated to follow their example in everything in life.
Saudi monarchy have a decent following from major tribes of Arabia, as far as Islam is concerned, that is as Islamic as it gets (binding agreement).
And one other thing, it's not your place to force upon us YOUR interpretation of what an Islamic rule should be. If you do that then you have to -by principle- accept SA's interpretation of what Jihad/Hijab should really be, and if you don't abide by their views then you should accept all kind of derogatory/inflammatory rhetoric from them just like the rhetoric you're spewing on us right now.