They are not "against it". They offer tips for selecting a groomer and suing negligent groomers. At no time do they suggest that taking a dog to a negligent groomer is cruel or irresponsible.  
Way down at the bottom of the page they mention dog owners might consider grooming their own dogs themselves.  So why doesn't the Iditarod get the same treatment? Why don't they offer tips to sled dog owners and leave it at that?