First of all, good judges, and they are out there, judge each dog against the breed standard and pick the one they feel comes closest. Yes, it is subjective to an extent. And, yes, I feel that there should probably be more ribbons withheld than are (but that's strictly an opinion). And, unfortunately, there are judges out there that are less than the best, or perhaps just not good for a particular type of dog (within a breed). For example, maybe a person has a Blue Merle Collie and when choosing which shows to enter notices that John Smith is judging collies at one of the shows. She also knows that Mr. Smith very rarely will put up a Blue Merle collie so the exhibitor does not enter that show.
As far as professionals winning more often, that's to be expected. Where showing is a hobby for you and me, for the professional it's their livlihood, so they have more at stake. Thus they have more time to spend working with and training the dog/s they handle. They also have more time and spend more money than most of us in learning how to best present a dog and how to groom and all the rest that goes into it.
Some breeds, for example most terriers, are more likely to be professionally handled than others, for example collies. But, owner handlers do beat the pros (including winning Westminster on occasion.
Are things always fair? Does the best dog always win? Are dog shows free of politics? Absolutely not! They are run by humans and as long as people are involved things won't always be fair and politics will be part of the game.
As President Harry Truman said once about politics. "If you can't stand the heat stay out of the kitchen." This definitely applies to dog shows, cat shows, horse shows and just about any other competitive event.
