The thing is, when he's in Canada, no one knows he's a police officer. He has no authority. He's a private citizen and expected to act as such.
For the record, this is what he wrote:
"I recently visited Calgary from Michigan. As a police officer for 20 years, it feels strange not to carry my off-duty hand-gun. Many would say I have no need to carry one in Canada. Yet the police cannot protect everyone all the time. A man should be allowed to protect himself if the need arises. The need arose in a theatre in Aurora, Colo., as well as a college campus in Canada. Recently, while out for a walk in Nose Hill Park, in broad daylight on a paved trail, two young men approached my wife and me. The men stepped in front of us, then said in a very aggressive tone: “Been to the Stampede yet?” We ignored them. The two moved closer, repeating: “Hey, you been to the Stampede yet? I quickly moved between these two and my wife, replying, “Gentlemen, I have no need to talk with you, goodbye.” They looked bewildered, and we then walked past them. I speculate they did not have good intentions when they approached in such an aggressive, disrespectful and menacing manner. I thank the Lord Jesus Christ they did not pull a weapon of some sort, but rather concluded it was in their best interest to leave us alone. Would we not expect a uniformed officer to pull his or her weapon to intercede in a life-or-death encounter to protect self, or another? Why then should the expectation be lower for a citizen of Canada or a visitor? Wait, I know – it’s because in Canada, only the criminals and the police carry handguns. Walt Wawra, Kalamazoo, Mich."
I interpreted this to mean he would have pulled a weapon, if he'd had one. You're quite right, though, that may not necessarily be the case.

Maybe he would have felt so secure, just having that weapon on him, that he wouldn't have felt the need to pull it. Maybe that feeling of security would even have led him to perceive the young men in a friendlier manner.
However, as I said before, I rather disapprove of using a gun as a security blanket. So, that scenario isn't really much better, imo.