Personally, I don't blame him much if at all. He can't be blamed for pointing out rules to someone where they are being flouted - what would other pax think about the rules otherwise?
When doing security checks / training, the use of it all is mitigated by telling people in advance what is happening. IMHO what should have happened here is that you should have only been given one bag to carry through in the first place (or was the fact that you had 2 bags meant as a clue to the dog handler?), in which case WTF?