Possibly they were training. Perhaps they compare answers. IMO, they seem over-paranoid to me as a yachtie, but it does happen. I have no reason to think you were specially singled out.
Americans complain about the fees
for the Quarantine inspection
. They are high. No one likes 'em. And if they've stopped in NZ first, NZ's Quarantine inspection
is no charge. Most yachties hate to give up their good food
, too. So, I agree, there are complaints.
We have frequently been overflown by Australian Customs
, polite and business-like they were.