I agree with most of that.I'm not a Saudi apologizes...but there's two major points....
They are a dictatorship in a very troubled region. They are already on shaky ground by supporting the US in a lot of ways. They are doing everything they can to hold on to power and supporting the US can only go so far before they piss off their own population. Their money given to fundamentalist groups is straight up bribery. They are obviously not a fundamentalist monarchy they are a monarchy governed by self-preservation and making money.
Second major point, there's no doubt we prefer a Saudi Monarchy in their current form over them being replaced. Saudi Arabia is where the Muslim religion started and is a very holy land for them. There's no doubt that a removal of the Monarchy would result in Saudi being the natural home of a new caliphate...backed by some of the largest oil reserves in the world.
So, I think it's easy to criticize them but the Monarchy there is balancing themselves are a razor's edge and the US has every reason to want the Monarchy to succeed.
If anything, this shows how our continued dependence of fossil fuels has some really bad consequences.