Perhaps to you or from your own personal perspective this is the case, sure. It isn’t obvious to me what people mean when they use the term Retail, unless I am already familiar with their opinions and perspectives.
Here are some common definitions of Retail as far as I am aware:
Retail can be used to refer specifically to the current latest version of WoW. This definition is inline with Blizzard’s folder schema that calls the latest version of the Classic series Classic, and the original WoW Classic 2019 Classic Era.
Some seem to think of the original trilogy as a thing, and that that is “Classic” - so WoW Classic, TBC Classic, and Wrath Classic would be Classic, and everything else may be thought of and called Retail.
At the time when The Burning Crusade originally launched, many players disliked many things about it, and stopped playing. Although I don’t recall the actual term “Retail” being used then, in today’s terminology, that would very much fit a Vanilla WoW/Retail dichotomous taxonomy.
At the time that WoW Classic was developed, Battle for Azeroth was the current version of WoW, so that was what people meant by Retail then. I suppose it would be possible that BFA, Shadowlands, and Dragonflight are Retail and everything else is Classic in some people’s minds.
I’ve come to think of all version of WoW as being retail and retail having no particular or special meaning, or perhaps that I prefer the meaning that it simply is a word chosen almost at random to represent the current latest version of the game, whereas every version that preceded was at one time at that version. Something like HEAD or Trunk, or Master/Main, or simply Current also seem to be used to represent this.
That is to say, it isn’t obvious what you personally mean when you say Retail, nor is it particularly obvious that there is a general consensus among WoW players as to what it means. In my opinion, it’s a rather meaningless distinction anyway, since it’s all WoW, though of course we all have our preferences.