I think it would've been a different story. He probably would've pulled and run over and tried to play..
That strikes me as "interesting??"
If I were to venture a guess. I would say that most likely you have a balanced dog. Those are dogs like Cesar's "Daddy" they can sense "bad energy" and they stay away!
In any case friendly or hostile your dog should be under control. But in this case, his "default" behaviour worked to your advantage!
So I guess...while you don't get full credit for "training" this behaviour. You do deserve full credit for picking this puppy! Yes a backhanded compliment at best but still you did good!
Some of us get dogs that are wiser than we understand! My Rocky once again saved me from making a poor choice in our most recent sigh...Pit encounter!
On a walk a couple of weeks ago, he was behind me off leash and I was talking to my DIL. Not paying attention, I forgot one of my rules! "Open garage door people in the yard working on cars ... "beware of dogs" ...ie cross the street!"
I forgot about the massive Pit/Cross that I knew could be there?? He came rushing out of his "stupidly" insecure front yard (no gate???) And came straight at Rocky like a heat seeking missile!!
I saw and heard him I told Rocky (off leash to "Stay" I got this!!!) I stepped in front of Rocky. I was more than ready to lay into the dog!!!
But before the dog got to me "Rocky" failed ...to "Stay," behind me!! instead, he stepped up stood beside me and smiled at the charging dog??
In that instant, my attention turned from the charging dog and to Rocky, WTH??? At that moment "the red mist" was gone and I was able to think! I now observed the charging, snarling dog slow down stop and sit and wag his tail, in response???
I was uh...unkind to the guy and told him to "control your dog" and we stomped off! Took me a few days and another poster to actually realize what had happened here! Apparently "Rocky" recognized that "sometimes" Daddy does not make "good choices!"
The real danger in that particular situation was not the "charging dog" it was "me!" Had Rocky done as expected, that dog was not getting by me!! But as soon as Rocky moved my focus shifted to him??
Bottom line, that makes twice, he has saved me from, charging dogs while I was protecting him! Pretty sure Struddell would have said "well" Daddy said stay and I guess he knows what he's doing???"
Sometimes we don't get the dogs want but we get the dogs we need!