I agree up to a certain point, but the US is in no position to destablize a bordering country, that's just not on the radar. Furthermore, the Mexican govt won't allow the US to project force en masse because it would be a sign of weakness.
The problem with Anonymous' plan was the lack of actual source verification, the chances were that it would pretty much just put out a lot of bad info, potentially endanger innocent people, and NOT achieve the release of their comrade.
I hate to break to you die-hard suporters, but Anonymous is not able to bring down Zetas. There has been banners hanging (next to dead people) spelling out what politician met with those dead guys hanging right next to them...what's happened? Not a damn thing. If you release names, you might actually HELP the Zetas (or even other cartels, there are about a dozen majors). The cartels are not dependent on the internet, therefore cyber-attacks will in the end accomplish NOTHING. If Anonymous had a super-powerful militia able to project power anywhere in the world at anytime, then they might have a chance at "stopping the cartels," but until that day - they will be entirely ineffectual, and only risk themselves by attempting to engage ultra-violent cartels.
This is just reality.
Counter-Intelligence. 
