Because they are:
-Biased
-Clueless
-Stupid
Some combination of that. Notice how when they get called out when they are acting like idiots, they have no defense for it that isn't easily refuted... Case in point: those guys support an air time limits. Why? "It stops things we don't like". Lol.
I really don't see why ad hominem and arguments to authority are so beloved in this community. If a random ****-throwing insane hobo happened to go beat Ally, ADHD, M2K, and TKD in the same sitting, would that make him the absolute authority on smash? How about a 5-year-old, who, after performing the same feat, recommends that we turn on smashballs and play on all stages? On the other hand, if you have someone explaining to you perfectly reasonably why his method of playing the game is the most competitive, he has to win a national before anyone takes him seriously?