Would you have a child free section of each view/room type offered? Child free lagoon view, child free garden view, child free king beds, child free double beds, child free preferred location, and so on? Unless you did this, you would still have people complaining. And Disney has shown that they are not willing to block off rooms ahead of time, so I can't see them blocking of a whole wing/building.
And then what about the people who are disabled but would also like child free? They could claim discrimination unless their needs were met as well. It would be unending trying to accomodate every person who might want child free.
I'm not trying to knock you for wanting an adults only wing, I'm just trying too show how it still would not satisfy some people.