From what I can tell, the issue (in terms of the dog's mental state) is not being confined (by a chain or chain link) but being confined alone. It just so happens that people who are willing to leave their dog outback alone are more willing to pay the costs of a chain vs. the costs of chain link.
There is a hug distinction between how sled dog folks manage their dogs and what should be the intention of the anti-tethering laws; the sled dogs are not alone and are not tethered 24/7.
Anti-tethering laws are just another example of a law to address a symptom of the problem and not the actual problem. The problem is not how people leave their dog alone 24/7 (tethered in the yard) but that people leave their pet alone 24/7.
