Globalising intolerance

David Farrar reported the other day that Senator Bob Brown, the leader of the Australian Green Party, has called for a “global parliament … under the grand idea of one planet, one person, one vote, one value”.
David wonders whether this notion is supported by the New Zealand Green Party, but notes that the concept “could never [happen] with so many countries presently governed by repressive regimes”.
I too would like to know whether the New Zealand Greens are supportive of such a concept.
Let us imagine for a moment that such a parliament were to be established.
Would the Greens be comfortable allowing a global parliament to ban things worldwide of which a majority did not approve?  What if this global parliament sought to outlaw homosexual behaviour worldwide.  Or even simply prevent legal recognition of same sex unions internationally?
Out of a global population of seven billion, there are about two billion Christians (of whom about one billion are Catholic), one and a half billion Muslims and a billion Hindus.  So that’s 4.5 billion belonging to religions that have historically been hostile to homosexuality.  I acknowledge that large chunks of the Western Christian population have fairly nuanced views on homosexuality now, but note that even the Anglican Church is opposed to legalising same-sex marriage in the UK.  Moreover, most of these 4.5 billion people live in countries in which there is next to no separation of church (or mosque or temple) and state.  As such, there is a very strong likelihood that a global parliament would hold a majority view against the legal recognition of same sex unions.
Would the Greens be content to see the rights of New Zealand gays infringed because of the religious views of the world’s most populous nations?  And indeed, what of the rights of women?  Equality between the sexes is more advanced in New Zealand than almost anywhere else, and a majority of the world’s women at this stage would most likely not be of the view that there should be full equality.  So would the Greens accept a global parliament abolishing our legislation preventing sexual discrimination?  Or domestic violence, for that matter, which is much more accepted in a majority of the world’s countries than it is here in New Zealand or elsewhere in “the West”.
If not, would they concede that the power of a majority of global citizens to impose their views on others via the ballot box ought to be limited?  And if they concede that, then why do they believe that a majority of New Zealanders ought to have unlimited rights to impose their views on other New Zealanders?
Why should a majority of New Zealanders be able to impose their will on other New Zealanders, but not a majority of foreigners?  Is that not essentially racist?
I don’t think the concept of a global parliament is necessarily bad, but I do think it serves as an excellent theoretical example of why the powers of all democratic institutions to interfere with individuals’ activity should be strictly limited.