a few mismatches make sense. for example the text saying aussie or the like, but nationality saying british, as they would use the id that allows them to work here I assume (and many children of expats are entitled to uk passports through the mother). The same applies to brazilians who have italian, spanish, german etc ancestry. They would get the european passport not necessarily the brazilian or argentinean, chilean, american, south african, zimbabwean, nigerian, etc as it allows EU work freely.
the dominant reason is of course to avoid stigma of certain nationalities. some countries have the stigma of certain practices to some/many punters (like lying on profile).