1) A trained FSB operative completely fell for a convincing enough social engineer, armed with nothing but caller-id spoofing software. Even though he was extremely apprehensive in the beginning of the call, he was slowly "eased into" talking top-secret stuff on the non-secure phoneline. This was so incredible that his last words on the call were "I was shocked by your questions. Was this OK that we talked about this on a non-secure line?". That's crazy. What chance do normal people have against such a good social engineer?
2) The amount of pro-Putin commenters in this thread (mind that some of these comments are dead), claiming that this is a CIA false flag or some such.