I definitely think it's a weird criteria. Everything you need to do to enter the DLC is part of the DLC story it's not like it's some ridiculous requirement what they're asking you to do it's not arbitrary.
Don't forget the most important thing: you need to own the base game. That's the deciding factor.
If SOTE was a simple, free, unnamed update (but same content as it is now) of the base game, everybody would agree that it doesn't make any sense to have Elden Ring again as a GotY candidate. Why? Because it's "only" additional content to a previously released title.