Because we don't like the game, and thus don't want it at events. We hate on the game to voice our opinions, and maybe get noticed by GimR senpai. If we get noticed hating on the game, it might not be at the major events. That's what we want.
Sorry to tell you that the world doesn't revolve around Melee. This isn't called "Meleeboards", it's called "Smashboards" for a reason. You may want to not see Smash 4, but given Nintendo's [lackluster but actually present] support for Smash 4 and the huge following it has [EVO had more Smash 4 entrants than Melee entrants:
http://shoryuken.com/2015/07/01/evo...released-see-where-your-favorite-game-stands/], there is basically zero chance of Melee ever being at a major event without Smash 4 [even Genesis will have Smash 4, and that's nothing if not an iconic Melee-focused tournament].
You are entirely free to dislike the game, but verbally harassing other human beings because they happen to like a different video game than you is not only incredibly rude, it's also extremely petty and quite childish. I frankly am shocked you would intentionally try to ruin other people's chance to enjoy a major event because you dislike the game they play... I for one may not understand most of the fighting games at EVO beyond a very basic level, and may even be bored by watching them, but I would NEVER seek to have any game removed from the event [barring a grossly offensive fighting game (Ex: intentionally racist), but at that point I'm nearly positive EVO wouldn't have it].
Even then, if you really want to hate on the game, I can't stop you. But I can shake my head at how immature some people in the Smash community really are, and also do my best to try to speak up and minimize the influence of people who would deliberately seek to exclude certain parts of the community because they want to enjoy Smash just like everyone else.