Earlier quoted context omitted.
Here is the video clip from General Alexander's congressional testimony three days ago, where he stated this was not happening: http://youtu.be/ZmBAxEWxDFs?t=1h29m50s It's not clear to me whether they were sworn in for this hearing or not, but if this new report is true, then this seems to be at least the second documented case of an exposed lie about the scope of surveillance during congressional testimony. The firs…
He might be interpreting the claim as being that Snowden could do that, which is, of course, false.
Alexander might have meant Snowden wasn't supposed to have that capability. Or that Snowden had it but wasn't supposed to use it that way, so he "couldn't" do it under the law (but could in practice).
It's hard to say; the testimony has often used obfuscatory weasel words and conveniently shifting definitions, and the avuncular grandparents in the Senate aren't exactly vigorous in their cross-examination.