I also have to disagree with this statement and the article in general. It's very difficult to say what terrorists use when they are living in the US, let alone make a general statement that they don't use them because they'd be stupid to use these services. That actually makes the argument for why using these services might be advantageous for them even stronger. If you (the general population) doesn't think they'd use it, that makes it more of a reason for them to use it.

Let me big clear that this is not an argument for NSA-type surveillance, however, I don't think we should be arguing against the surveillance using general statements or more accurately opinions like these. Argue against surveillance with more factual/strong cases.