They're not, while I'm sure there are some that have their reasons for not wanting Legacy servers, it's just a loud handful like always. I've been re-subbed for a couple weeks cause a co-worker buddy was pushing me to give it another go, and I do admit there's just not another MMO out there like good ole WoW.
I've not played on a WoW private server. Would I pay for, and play on a legacy server if given the chance? Absofuckinglutely.
I've been here from damn near the start, my first major content patch that I was around for added Dire Maul to the game. I was a steady raider from Vanilla times all the way through to MoP when I finally just lost interest in it, then came back for WoD. Dire Maul came out in early 2005, Siege of Orgrimmar was when I lost interest, that was released in late 2013, which makes 8 solid years of raiding and playing in WoW.
8 years of exploring this weird fantasy world, playing with friends, slaying internet dragons, exploring crazy, dangerous, and spooky places. I have such fond memories of meeting people and becoming great friends in this big virtual world, people hated Stranglethorn Vale, I loved it, it was one of my favorite zones because it felt so wild and a full environment. I loved Darkshore for being the first "hodamn this shit's real" area as the first char I ever played WoW on, Teldrassil was teddybears n kisses compared to how dark and spooky Darkshore was. The Barrens were a giant region for the Horde that Alliance had nothing to compare to except Ashenvale, which everyone hated anyway. Feralas had this dark, foreboding mystery to it, and one of my favorite zones was Desolace, where I remember first encountering an opposite faction member, and we communicated through socials, helping each other do quests in Thunder Axe Fortress. I remember how fucking epic it was doing Zul'Farrak for the first time and getting to the crazy pyramid gauntlet part, with a group of strangers that had formed up and worked together for more than an hour slogging through that dungeon.
All these places have a lot of great memories attached to them, and right now...Well, they're too streamlined. There's no real danger out there unless you blunder into an opposite faction town. There's no fumbling from Ashenvale to Azshara and going "Hey why are those ghosts showing as ??? level? That's we-OH GOD", there's no tip-toeing around the shores of Feralas which have a bunch of elite giants wandering around, same for the eastern shore of Strangelthorn. Now even if you do encounter an elite, it's generally pretty easy to steamroll the damn thing.
For real, people do look at Vanilla through incredibly rose-tinted goggles, absolutely! There were a lot of game mechanics that were frustrating and grindy just because that's how it was done, and it's good to be rid of some of them. But there was also a very, very different world (of warcraft) to interact with and interact in. Cata streamlined everything so much that you didn't have to ask questions, didn't have to go exploring, didn't have to team up with strangers to take down big toughguy quests because they reward a blue gear, oh shit!
I got to experience those things. I loved that, so very much. But right now, it's gone. There is absolutely no way for me to share that experience with anyone, there's no way I can tell someone "Just jump in and immerse yourself!". I can't even fuckin go back to Darkshore and sit on that rock I used to sit on and fish for hours, just to give people fish for that Gubber Blump quest. People would come up and chat with me, just sittin' out there fishing on a boulder.
Now like I said, the game's different, vastly different now. Some things for the better, some things for the worseWoD but one thing is for certain, that WoW has lost some of the luster and charm it used to have.
Whether Legacy servers come from Blizzard or Nostalrius or wherever, doesn't matter. What it amounts to, is that everyone deserves the chance to be able to experience what made people like me love this game.