If 100 people entered a Melee tournament and 99 of them played Ness and one of them was Ken playing Marth, Ken would still win. That's because Ness sucks in Melee. It has nothing to do with how unpopular he is. He is simply an inferior character. Even Simna who is undoubtedly the best Melee Ness player could not beat Ken with Ness (I haven't seen him playing very many big names other than that but I doubt he could beat m2k, pc, cort etc. consistently with Ness either.)
Although the gap between tiers in Brawl is debatedly less expansive than it was in Melee, the results are the same. Some characters are worse than others no matter how popular they may be. I'm not saying that Ankoku's list will give us a perfect demonstration of which characters are better than others in a few years, but right now with the metagame developement where it is, this is a moderately accurate portrayal of which characters will do better than others. In a few years it may very well be different but that's not what this list is about. It's about now. And if you really don't think it's accurate than trying playing Ganondorf or Samus up against a good Snake player. You might find that you quickly change your mind. I honestly see no reason for debate over the validity of this list given that it is based on actual tournament data.