There's absolutely no explanation for this besides stock issues. As someone else already pointed out, even Apple prices are lower in Brazil.
These are stock constraints, there's no other understandable explanation.
Watch this price going down at least R$ 1000 after the first 6 months.
The explanation is simple, there are enough people in Brazil who will get it at those prices, as long as they exist it will continue to happen, and not only with Sony, with any company.