I get what you're saying- but you're wrong in some ways.
Firstly, they said it "isn't a water park, its a water theme park". So that is true, is it not? Wet N Wild, or name your other generic water park like Hurricane Harbor, etc- while they might have a similar number of rides, they are just a bunch of slides and concrete. Aquatica, while nicely landscaped, is not "themed" either. BB and TL are, and should be "water theme parks" as well or "themed water parks"- whatever youd call it isnt the issue- they are themed.
So its on Disney, really, to have not differentiated their water parks in their domestic marketing from some generic water park.
Make no mistake, Volcano Bay is no Wet N' Wild. It isn't "a water park that replaced a water park". Its a water theme park that replaced a water park.