Please understand, Blizz can do thatthing, simply, because back in classic times they gave the game to the players. They didn't have to/want to encourage or discourage ppl to use addons with the game, they just let that gate, that possibility open, so the players' classic experience became an addon+game combo, instead of just the game without addons. And the rights to alter their own product, how it handles addons (which are not part of the game and are not designed/published by Blizz, only by the fanbase, the players), is completely legal, because it's their own product. You are not entitled to demand that combined experience from Blizz. You are entitled to demand the classic game only, not the addons.put two fingers inside each of their ears repeating "we (they) just provide the game"
In a perfect world back in classic WoW you should have played the game without addons, and in the future you are going to play it without addons, so that's the most similar classic experience you can get.
In reality, you played it with addons, and in the future you are going to play it with addons. It's how it works and Blizz provides the game for it. And don't be in the false hope that you are going to experience classic WoW on a day in the future on the exact same way you did in the past. It's repeating an old game in the future, not the exact same memories from the past.