Which is the reason that many agricultural diseases that plague the rest of the world don't exist in either Australia or NZ.

Quite well evidenced, when Australian (and NZ) beef was being imported into many countries when Mad Cow Disease was endemic in many beef producing countries.

Also the same reason why Australian (and NZ) chicken was very well accepted during SARS and other similar Chicken based endemics.

I'll let you draw your own conclusions - but the rules are there for a purpose, and it isn't "geographical and historical xenophobia".

BTW - why does the US require fruit being delivered from Hawaii to be certified and/or screened??? Surely this is a similar form of "geographical and historical xenophobia"...

Oh, and I've had my bags x-rayed when entering the great old U.S... I would have loved to see their faces if I commented that they were doing it for "geographical and historical xenophobia" reason - and especially if they found something they didn't like.