the thread was about someone that had a puppy, and didn't like that her trainer wanted her to use a kind of collar, as was told by the trainer the same as you think that a harness will let the dog pull... however that is something I totally disagree with. A dog, especially a puppy can be trained to walk nicely with anything on. If you are relying on equipment to make your dog not pull then your dog is not really being trained. A dog should be taught to walk nice no matter what equipment it has on.
The thing is with dogs with sensitive trachea's they can usually pull and know how much force they can use. However the person doesn't so when they pull on the dog or very young puppy, to keep it from danger , like an aggressive dog, they can do damage.
again this is just imo.. I have a shih tzu lhasa and I would have NEVER trained him with a collar at 7 weeks, especially a martingale or choker. But my lab had a martingale from a young age.
This I am saying because at 7 weeks, the pup should still be with mom and littermates. It is a time for bonding and play. You can start training yes. But the pup is still too young to be out socializing, the wont be able to have all their shots yet. at 12-16 weeks, you can start going nuts, especially with a large puppy. But at that age I would not be walking around other dogs and puppies.
again it is my opinion, doesn't matter how many links you have to show that others have that same opinion... You can teach a pup to walk nice with a harness, not true that they are going to pull you. I always only use a harness on my little dog and he does not pull, because he was rewarded for staying close. Relying on a collar and saying that the dog will pull if in a harness does not sound like training imo...