It was opened by a children's author whose books were banned and she wanted kids to have access to her books and other banned books and let them know that people don't want them to read them.
I get his point. I've seen Barnes and Noble feature banned books at the front of their store. It's a good thing to have available, but it's pretty standard for book stores to have banned books.
My locally owned bookstore has a display featuring banned books. It's not an entire store of banned books, but I think that's good. I don't think a store with only banned books would be viable in the long term.