Millions of people played World of Warcraft Vanilla WITH add-ons. If you don’t like that fact then go find a private server where they’re disabled and stop trying to CHANGE the Vanilla experience for everyone else.
Auctioneer, Monkeyquests, Flexbar, Gatherer, etc… all were fairly popular add-ons and all were available less than 90 days after the game was released.
If you don’t like add-ons. Don’t use them. If you don’t like other people using them go find a private server where they’re banned. That’s not World of Warcraft Vanilla.
My first character was a Dwarf warrior. I hadn’t even gotten out of the starting zone before another player recommended an add-on to me and I had no idea what they even were and told me a website to go to.