Also, it's clear that sanctions are a much more powerful weapon than invasion. Western sanctions (or embargo) on SA oil would certainly put them in a tight(er) spot.
Of course, it COULD be bad. Real bad. Hand-waving away such concerns is irresponsible. Having a major oil source friendly to an often hostile nation could have real, even deadly drawbacks.
But so too does always turning a blind eye. If we had gotten into this relationship and worked to reduce the threat (such as investing in other energy sources) we'd be in a better position, we could be at a point to change the relationship at reduced risk. We didn't, and we need to face the concrete realities we're supporting out of fear of hypotheticals.
Because now we may be safer, but we're supporting what we proclaim to be against. When we wield moral superiority, it's undercut. When we tell our children to be patriotic, we know the legacy we're leaving them.
Since the start of the cold war middle eastern states have balanced/played off against each other between the US (and the west) and Russia (previously USSR) when it comes to weapons and lots of other things.
I mean the Egyptians had soviet supplied fighters flown by actual soviet pilots fighting against the Isreali's in American and French supplied air craft.
The US sold Israel better fighters, the soviets sold their potential enemies better SAM's.
Or Are you not aware that the monarchy is already Islamic, of the kind least tolerant towards personal freedoms?