The issue isn't that the design and merchandise of the Avatar project borrows from existing world cultures- it's that by using the same corporate effort to present and market culture "authenticity", the Avatar project brings in to stark relief the company's previous efforts to do the same with the Africa and Asia lands. People have sometimes described Disney's Animal Kingdom as, "Third World Tourism ****ography", in that large portions of the park are dedicated to collating some of the more singular sights and sounds from the designers' endless world fact-finding tours, but most especially those that depict foreign poverty, in order to convey a more heightened sense of the exotic. There's a very thoughtful essay about the park, pre-Avatar
available here. Amalgamated, semi-fictional places (Harambe, Anandapur) are created in order to avoid the designers being tied to a specific place or culture, and these intentionally "exotic" culture stews are then presented as part of a wider, park-wide narrative that is ostensibly about mankind's relationship to animals. That's always been one of the key differences in the Animal Kingdom's approach from most other theme parks. Unlike say, the Wizarding World at Universal, where the magic and castle are all presented as real and the overlying message is, "Isn't this cool?," the subtext from what's presented at the Animal Kingdom has always been, "You need to learn something from the way these people live." What is different now is that by using the same narrative and design techniques seen in the other lands ("authentic", "cultureally-inspired" merchandise in the gift shops, pseudo-"ethnic" garb for the cast members, etc.) is that the park is going to put a 2009 James Cameron film on an equal topical footing as aesthetically distilled notions of "Asia" and "Africa." I don't envision anyone from the social justice/culture appropriation sphere raising "pitchforks" over this, my observation is simply that by adopting the same theme park design techniques and modes as the other lands, the Avatar project is serving as a satire, intentional or not, of the rest of the park.
It's the self-parody, not any potential offense, that I find interesting and amusing, and I would love to know what sort of internal conversations were had about this.