The problem was first noticed in relation to Australian men, but the problem
with New Zealand men is (proportionately) much greater.
There seem to me to be two reasons for this:
Men realise that New Zealand is now run by women for women -- instead
of by men for women and children, as has traditionally been the case throughout
history all over the World. For this reason, many men see no reason to
come back, once they have escaped. As a letter to the New Zealand Herald
by Charles Purcell (on 29 July 2005) put it: "Our women need to give
men a much better deal. They should listen less to radical feminists of
indeterminate sexuality and give their men a fair go."