Can you be more specific about what massive reductions in Europe-wide security resulted from the publications, and how they presumably would have stopped the Charlie Hebdo attacks?
Whenever you see "terror arrests made during dawn raid" on the news in UK, it's easy to dismiss it. But it happens pretty much every month now, and has been like that for a couple years now. Every one of these raids is potentially to stop a major terror attack; but the public is never told of the exact details of what they were plotting because otherwise that would defeat the purpose of averting a terror attack.
Osama wasn't keeping an air-gap because of Snowden. He was doing it because Clinton was calling in cruise missiles on terrorist cell phones back in the '90's.
I think a better argument is that only stupid terrorists talked on the phone/internet and eventually they would nearly all be "naturally selected" out of the "gene pool" until all you have left are the smart terrorists who teach their disciples how to be smart.
Unfortunately the stupid terrorists were also the ones least likely to successfully carry out a significant attack.
There are two options here. One is that there really are monthly plots to attack civilians in the UK, and these raids are genuinely saving lives. The other is that bring able to point at terrorists threatening our city centres is a very convenient way to distract people from the real issues.
How many of these raids are against real credible threats, and how many are people with a grudge getting hit for discussing the wrong thing? Unfortunately we're unlikely to know since so many of the trials are held in secret to protect the evidence being given.
Did you sleep through V for Vendetta?
the public is never told of the exact details of what they were plotting because otherwise that would defeat the purpose of averting a terror attack
That's not how rule of law works! If someone is accused of a crime, it is vitally important that it be described and proved in public at a trial.
We've been round this in Northern Ireland. Diplock courts, internment, etc. It's not justice and it just breeds resentment. It's completely critical to the long term success of antiterrorism that British muslims do not feel that they're going to be victims of arbitary arrest and detention.