"2) The bite would be enough to make him feel threatened, and he would fight back.
And he is bigger and often physically harder than many nippy herding breed dogs. So there is a strong chance that, while it would be bad for my dog, it could be worse for yours."
Also this. If a large and powerful dog does not take corrections well, that dog should NEVER EVER EVER EVER be in a position to approach strange dogs. Period.
My other dog also hates being approached by strange dogs. He weighs 6lbs. If a dog has ignored the equivalent of him shrieking "I KILL YOU!!!" (please imagine that in a very high pitch with a thick Mexican accent. I do.) I have no reason to believe that dog isn't going to eat him him it finally gets close enough for him to bite.
So what I'm hearing is "I wish owners of small, vulnerable dogs would understand that my dog is bigger and stronger and also ill-mannered. They need to teach their dogs not to freak out when some big dense lunkhead starts looming over them threateningly, because if they accidentally provoke him in their terror is would be very bad for them."
Well, not what I mean... in the sense that I am not putting all onus on other people or on their dogs. And believe it or not, this is not even primarily about my dog. I work hard to keep mine away from dogs that I believe would respond poorly to him, and not only that, but it takes a lot to get him to bite (he's dense about socializing AND about pain

). However I am sure that if a dog toothed him in the right spot and caused enough pain or latched onto him or otherwise seriously scared him, he would fight back.
As for NEVER EVER EVER EVERs.... you can bet on those if you want, but I don't believe in them. I agree that allowing dogs with poor social skills that might meet bite for bite to socialize very freely is bad, but I'm a "plan for the worst" kind of person. In any case, you could about as easily say that dogs that might try to nip if another dog bumps into them by accident should NEVER EVER EVER EVER be allowed in spaces where many dogs are likely to be in close proximity (aka a ton of training spaces). I'm not fully on board with either idea because I think management of either thing can prevent accidents.
Now, what I am saying is that if your dog is very intolerant of other dogs, bossy and nippy, then yes - it's in your dog's interest for you to try and defuse situations yourself before throwing your hands up and letting your dog physically correct another dog, and you definitely should not look on with some amusement complacent in the assumption that your dog's biting will scare the other dog into submission (perhaps especially when that dog is bigger than yours).
Because while I work to keep my dog-that-might-bite-yours-if-yours-bites-first dog out of situations where he could annoy other dogs into biting, not everyone does. So yeah. You can rest comfortably in the outraged knowledge that the fight wasn't your fault because that big dumb labrawhatever was being rude, or you can prevent the fight by intervening on behalf of your dog before they attempt a correction that could cause the confrontation to escalate and/or by working with your dog to increase its comfort level with other dogs to whatever extent is possible.
Neither of those things actually undermines necessary attempts to train overly exuberant dogs to be calmer and train their owners not to let them run amok.
Do what thou wilt, etc.
So while I do see now what your point was, I'm also not shocked or bothered by anyone's reactions. Because seriously, many of us have been the person with the "over-reactive" dog. I was that person yesterday when I was hiking and a dog ran up to us with the owners still way out of sight on the trail. It's frustrating and it can put your training back, and you feel like a horrible person when you are trying to scare off the dog before it makes contact with yours, and when I see this:
it just plain scares the crap out of me. Because if I have my 11 year old dog under control, and I call her back and put her on leash but your dog still approaches rudely - she's going to snark. And if your dog (generic 'you' since I know you clarified that your dog doesn't get put in these situations, which is great) over-reacts to what you see as my dog's over-reaction...while, you are right. Your big, hard, young dog could quickly injure or kill my 11 year old 33 lb. dog. And if mine is on leash and I'm not actually in a dog park (spoiler - I will never be in a dog park), it is going to be 100% the fault of the person whose dog ran up. And it is not going to be a nice day for anyone.
I get that. My dog used to get so vocally emotional when other dogs came into view that he became very difficult to control even on leash, and on more than one occasion I had to ask people whose dogs were off leash in areas with leash laws to
please put their dogs back on leash so we could get by. And I've had them ignore me and had it make my life harder. I'm well aware of how well-intentioned out of control dogs can cause problems.
And yeah, the idea of my dog somehow getting out of my control, going up to a space-sensitive, nippy or bossy dog, getting bitten in a way that sets him off and a fight happening? That scares the crap out of me too. But that's part of why the persistent assumption by some people I have run into that their dog that is quick to correct will surely teach the other dog to behave and should be allowed to correct without any critical eye being put to it bothers me. It's not an immediate question of fault (although usually the owner of the dog trying to approach
is at fault), it's a question of preventing a potential fight vs letting it potentially happen.
But, it's hard to try and communicate that worry without almost sounding like I'm trying to threaten people with my dog, when of course in reality it's not even my dog I see this most likely happening with.