I don't get the extreme devotion to Melee either; I'm not really into competitive Smash, but it seems that the Melee situation is like if people started demanding that Street Fighter III: Third Strike (specifically, the Dreamcast version of that game) should be a headliner in EVO, saying that it should take priority over the most recent games in the series and complaining if it didn't get preferential treatment.
Maybe I'm just not informed enough on the topic, but you'd think that after nearly two decades of playing the same handful of characters on the same handful of stages, there's only so much that could be done with the game competitively. It probably doesn't help that I saw
this Reddit post this morning, where someone was (un?)subtly trying to say that Melee's the better Smash game because it had higher viewership at one particular tournament.