" how would a second or third or fourth generation Australian...

" how would a second or third or fourth generation Australian child whose family are decent responsible people feel when
they hear a Cabinet minister Minister saying it was a mistake their forebears were allowed into Australia"

If you dont know why not ask them? You might be surprised at the answer. I'd say they would be able to tell you how to tell the good from the bad and very easily apply that to screening for entry.