Two follow up points:
1). I am quite happy to accept that my analysis of the reasons for going to war in Iraq might be way off base (or as you put it, "hogwash"), but at least it puts forward reasons for the invasion that, in the absence of the WMD argument, have some internal coherence. If we accept that WMDs were never the real reason for the war, we are left with only two possibilities. The first is that the US went to war in a fit of pique or private greed on the part of Mr Bush and his inner circle. The second is that there were reasons of realpolitik for the war, which being by their nature amoral, but perhaps necessary, could not be used as a public justification ( "War is merely a continuation of politics"). If so, it is legitimate to question what they might have been.

2). IF the Saudi princes fall the US will be powerless to intervene, just as the US failed to protect the Shah in Iran. Whether an emergent Saudi rebel regime cuts off oil to the west (it might for example redirect most of it to China) or not, it is a fair bet the price will go through the roof.

As far as Saudi dictatorship is concerned they have, unsurprisingly, many enemies. For example, in 1979 Saudi dissidents stormed Mecca. Among the demands of the insurgents were that Saudi Arabia stop selling oil to the US. The rebels were ‘evicted’ with the help of French troops. ALL the survivors were publicly beheaded. The opposition has been more sedate since then, but it exists,
opposition

Obviously my argument is a hypothetical, but it is on the basis of hypotheticals that governments must act to protect their interests. There is a world of difference between doing right, and doing what is right for the nation.

(Saudi opposition http://query.nytimes.com/gst/fullpage.html?res=9F07E2DB1131F934A15753C1A9659C8B63