"Good and bad oppression" among Islamist governments?

Comment published on New York Times online blog in response to article, “Saudi Arabia and U.S. Clash Over Khashoggi Case,” October 14, 2018:

There is an interesting question about US foreign policy towards Saudi Arabia in recent decades. It has to do with the putative ideological or moral motivations associated with US support of certain regimes: that is, with the choice of allies. The context references both "Islamism" and oppression/tyranny. We are supposed to want the world to embrace "democracy" and refuse "extremisms."  

So why has Saudi Arabia consistently been a US ally? Their oppressive, premodern government oppresses and kills women, gays, and dissidents and cultivates extremism. The most prominent counterexample is Iran, not a model of good government nor kind to all dissidents, but moderate and modern by comparison.  Yet it was in an "axis of evil." Our government must need to carve up the world between the righteous and the damned. It is tempting to say that it should, but moderately.

Could it be that moral/ideological reasons for the choices of allied and enemy nations are marketing points, while the real reasons are more material geopolitical ones of things like resource control? Pity. One would like to believe that the world's people mostly want not just power and wealth in the hands of their rulers, but, like us, justice and a good life.  

Demonizing the Saudi kingdom might not be the answer, but criticizing your friends and allies is an easily forgotten virtue that might have been more practiced, including when belligerent talk was hurled at less worthily chosen regional foes.