What's the alternative? Invade with guns blazing? That didn't work so well for Iraq; it led directly to ISIL. It hasn't worked out well for Afghanistan either. We already tried deposing an Iraqi government we didn't like and setting up a friendly government, and it got us here. How is doing the exact same thing going to work this time?
As for DeBeers, that didn't work because we (western nations) haven't actually done anything to DeBeers to stop the diamond trade. There's a DeBeers store not far from me in Manhattan NYC, even though they should be banned since they violate lots of anti-trust statutes. If we aren't actually going to hold corporations accountable to our laws, then we deserve whatever happens to us as a result.
If we would get off our asses and build SkyTran so we didn't need cars, we wouldn't be very worried about oil, but we're too stupid and shortsighted to free ourselves from our oil dependency, so as far as I'm concerned, we deserve whatever happens to us as a result.