What if someone then wants to make an Aquaman movie featuring Amanda Waller are they allowed to just ignore the events of the previous Wonder Woman movie? Are they allowed to kill someone big and make them unavailable for future movies? Can they use a different actor for the same character? Can two characters who were friends in one movie be enemies in another with no explanation? How far doe this lack of a mandate go? Shyt can get confusing rather quickly.
No, they said they will have continuity just not make everything connected towards some over-arching storyline.
So if there is nothing in a previous Wonder Woman movie that requires being mentioned in an Aquaman movie then there is no reason to mention it.
So if Character A dies in a Wonder Woman movie then that character won't be showing up in Batman's movie.
If Chacter B and Character C hate one another's guts in a Superman movie then they will continue to hate one another's guts in the Flash movie if they appear in it.
Its really not that complex a concept.