Claiming that Snowden has aided al Qaeda et al is as ridiculous as the notion that if you smoke cannabis you're funding terrorists!
The free release of information will always help the "good" and "bad" sides. Doesn't mean we shouldn't do it.
Snowden just told the everyman what the shadowy figures already knew.
"Supporters of the Taliban and al-Qaeda in Afghanistan have been getting U.S. military contracts, and American officials are citing “due process rights” as a reason not to cancel the agreements, according to an independent agency monitoring spending."[0]
[0] http://www.bloomberg.com/news/2013-07-30/al-qaeda-backers-fo...
That's definitely the official party line but there's no reason to believe it's true. For a decade before his death there was a constant stream of news stories talking about how he and other top al Qaeda leaders used disposable phones, had trusted family members hand-courier messages, used code/slang to make messages harder to understand, changed locations frequently, etc. because they knew that the US had the ability to intercept their messages, as did anyone who had read a newspaper or watched a movie made in the last few decades.
The only news in the Snowden leaks was that these capabilities were being used on such a wide scale and that the NSA was willing to weaken everyone's security to make such large-scale wiretapping earlier. That came as a surprise to many in the tech industry because it was both risky and unnecessary for traditional targeted intercepts but it shouldn't have been for anyone who'd been paying attention in the 90s when things like the Clipper chip or other mandated government key access schemes.
If your cannabis was grown by a nice American farmer then you're good. Hard to know how you can know that, though.