Most of the positive reinforcement trainers here are dopes - in the international circuit/outside of my city I'm sure there are wonderful, effective, properly firm positive associated trainers that do wonderfully with their dogs. I'll look into what you mentioned more.
How many have you met? I know quite a few wonderful, positive trainers in the Vancouver area, so I don't know where you are looking to find all these 'dopes'.
And in regards to the "use whatever works is great, every dog is different!", I am just going to come out and say that I think that is a tub of baloney and a poor excuse for people who don't really know what they are doing. Yes, every dog is different but really, the same principles apply. Sure you might have to tweak how you manage them or how you show them the desired behaviour, but ultimately it comes down to
dog's repeat behaviours they find rewarding, and discontinue behaviours that lack a reward or that they associate with something negative. It seems like people are afraid to say that one way is better than another and choose to be politically correct: "well every dog is different so if something works than go for it!".
The thing is,
lots of techniques do work. Hell, if you watch Cesaer Milan you can watch physical domination and the application of fear and pain work in the span of about 10 minutes for a dog who was previously acting in some sort of extreme manner. However, what people lose sight of is the
consequences of using a method that undermines your dog's trust in you. I could have used leash corrections on my dog to teach him to heel and you know, they would have worked. The by-products of that though would be a slower heel and less enthusiasm in the ring. A more serious example could be a dog who growls when children pet him over the head. If you correct a dog for growling, you will probably curb the growling. What you haven't changed is the dog's mental state (fear), and so next time a child comes to pet him, he may react with a bite instead because he knows now that to communicate to you that he feels uncomfortable will result in a negative outcome.
Behaviour, animal behaviour, dog training... This is SCIENCE. It's time we started treating it like science and accept that yes, there are better ways to do something. As a community who have the resources to know better, I think we should have higher standards when it comes to proclaiming something is working, and working
well. Let's stop accepting "well, if it works it works" - our dogs deserve better than that.
ETA: To give a human example, I had a math teacher who thought that I, as a student who struggled with math, could learn my multiplication tables from her belittling and humiliating me in front of the rest of my third grade class. Ever math block she made an example of me, and you know... I did end up learning my multiplication table. However, I still to this day as a 20 year old get anxious when I have to do math and someone watches, and I have avoided taking any math courses in my upper years. Her method worked, I memorized my multiplication tables... But at what cost? I still to this day believe my aversion to the subject is rooted in having had early, highly negative experiences with it. So while many methods may work in the most rudimentary sense, I think it is doing a disservice to put them all on equal footing.