I don't. Imagine that the people in Brazil (or in South America in general) also wanna see exotic megafauna as we in Europe or North America do. Further more, exhibits for those animals can be built much cheaper and the chance of getting more space for animals is also bigger then in most zoos in European countries NORMALLY/MOSTLY. However, I agree that - because of the political circumstances -, giant pandas could be an exception (= not an exotic species that MUST bee kept in a South American Country)
Awareness of conservation of native wildlife is important, no question. But like zoos in Europe or North America, zoos in Brazil are (or at least should be) able to fight on both places.
I agree there is a desire to see exotic species , but I believe the notion that visitors expectations are predominately geared towards seeing exotics has been conflated and is a rather lazy and generalized belief. Furthermore, I think this kind of assumption actually does have a negative impact because it leads to a greater valuation of the exotic over the native. In regions like Europe and North America which are comparatively low in biodiversity and a lower need for conservation it might be ok and understandable to prioritize exotics but Latin America has some of the highest (if not THE highest) biodiversity rates of plants and animals in the world.
For example, take this case that occured recently in Brazil of a well intentioned but ignorant girl who as a statement of protest against the burning of the Amazon created a body painting featuring the Amazon rainforest burning with giraffes and elephants in the background. The girl was slammed on social media ( and wrongly in my opinion as I hate twitter mobs and bullying of that kind) and the case was highlighted because many felt it revealed a total lack of awareness towards native biodiversity.
Makeup Artists Giraffe Tribute To Amazon Fires Slammed - Ananova
Many on social media criticized the Brazilian education system and suggested that it revealed flaws , but zoos may also be said to be organs of education couldn't they ? and I personally can see a strong connection between the two. There are some examples of zoos in Brazil that do amazing work in environmental education of the public about native biodiversity , those that come to mind are Sorocaba zoo , Bauru zoo and Gramado zoo , but the overall trend is unfortunately the opposite.
Furthermore , there is the issue of funding and finance. Latin America is a region of the developing world and unquestionably it just does not have the same economic resources that are available to zoos in the developed or "First world". The costly emphasis on maintaining non endangered African and Asian megafauna in zoos has been criticized even in Europe and the United States. So consider if you will what impact this prioritization has in terms of the funding of conservation programes of native species.
Ultimately the developed world of Europe, the USA, Canada , Australia etc. have both the resources and the luxury to focus their attention on maintaining zoological collections of African and Asian megafauna. However, I believe that the prime focus of zoos in Brazil, Colombia, Argentina, Mexico should, out of necessity and given the dire need of ex-situ conservation, be centred on native biodiversity.