The commenter you cite certainly doesn't articulate it very well - his comment is pretty knee-jerk with a healthy dose of fear mongering. There is a reasonable argument buried in there, though (I think). From a civil liberties point of view, it matters a lot more to convey to the public an understanding of who and why they're targeting rather than how. Here's a hypothetical, admittedly contrived analogy:

We've all seen crime movies where the criminal calls the police from an unknown location to make their demands and state what horrible outcome will occur if their demands aren't met. They're using the communication method to hide their location and (sometimes) identity. The police immediately flip on their call tracing device which starts counting down the time it takes to identify the caller's location. The criminal mastermind always hangs up with 2 seconds left on the clock because he knows it takes exactly N seconds to trace the call, for whichever value of N the scriptwriter chose. Fast forward a few years and our hypothetical police department now has access to technology that allows them to trace calls phone calls instantly. Until the criminals find out about it, they'll continue to call in and make their demands, giving away their location and enabling the protagonist to jump in and save the hostage or defuse the bomb or whatever. When the knowledge becomes widespread that phone calls are instantly traceable, the criminals start conveying their demands through some other non-traceable means. The advantage moves from the side working to protect the public over to the side working to harm it.

The only people it would benefit to have outside knowledge of this technology are the ones being targeted by it. It doesn't matter to general public how the police are getting their information, only that it's being used solely against legitimate targets. What the public needs to know is that independent review is being conducted to ensure the technology isn't abused and turned against them, and to be immediately informed if it ever is. Showing the public the police department's sources and methods in my hypothetical example had the net effect of making the public less safe. In real life, if it turns out that the NSA is establishing a huge Orwellian surveillance network for nefarious purposes then the public needs to see real examples - politicians being blackmailed, backdoor financial manipulation, ordinary people being threatened and coerced, etc. That would enable the public to stand up and take action against the NSA; if the public can't get their elected government officials to stop overt abuse, that's when a leak of sources and methods would be justified so that the public can protect itself. If it turns out that the NSA has been using its technology to collect against legitimate foreign intelligence targets, then the public hasn't benefitted at all from finding out how the NSA collects against its targets.

Personally, I prefer the solution mentioned recently on the EFF website [1] - establish independent oversight panels with both the legal and technical expertise to identify abuse and either stop it or notify the public.

[1] https://www.eff.org/deeplinks/2013/10/47-prominent-technolog...