Have you read "Ethical Oil" by Ezra Levant?
(Yes, I know, THAT Ezra Levant)
His argument doesn't fly with me. Most of our goods are produced in despotic developing countries with terrible human rights records. So if you're going to follow that argument you're going to have to stop buying most things and call them evil.
The only way to make despotic regimes less despotic is to trade with them so their citizens make more and more money, and by extension become more educated, and with that new education/knowledge they begin to figure out how crappy their government is and attempt to reform it. That's how development tends to work.
In the end, we don't need bad relations with the Saudis, but we also shouldn't be pushed around, but from their perspective nor should they. Somebody has to concede in this situation. The plain fact is that the Saudi gov needs the west on their side much more than the reverse. For us it means oil prices and economic health, for them it means the security of the Saudi regime itself against its regional enemies, notably Iran. We don't really gain anything by having the ability to tweet about human rights abuses which will have little influence on their politics.