You ask, "Why is everybody embarrassed to be associated with the Exclusive Bretheren? The vast majority, if not all, are certainly decent law abiding citizens who pay there own way in the world.

Surely they have more rights to a say in the political future of New Zealand than Labour's freeloading lackeys. "

My answer is simply that the basis of their gathering together is false. They have succumbed to a doctrine that has its roots in commercialism, and not according to the teaching of the Bible. One only has to cast a cursory glance over their credo, in order to uncover the falsehoods that their basis of fellowship rests upon. They claim for instance that their leadership is an unbroken and divinely appointed line, where it is in fact determined on something far less than divine. The leadership has been shown to be corrupt, bullying the rank and file for money, indiscriminate as to marital links, a leader who claimed rights to any woman in the fellowship, and indeed was found in bed with another man's wife. The same leader, an alcoholic and given to exercising "authoatative ministry" over the flock, which effectively split familial links asunder, and the suffering of the flock did not end there.
If they want to have rights to a say in the political future of NZ, that is indeed their prerogatve, however the edict not to vote would seriously hinder such a voice. They instead chose to throw money at the NZ political system, and it simply backfired on them, religion and politics ought to be mutually exclusive. Many think that the Church should keep out of politics. A great many more think that the Prime Minister should also keep out of politics.
As for me, I have firsthand and personal evidence of Exclusive Brethren misconduct, and perhaps am one of the few that knows the REAL story on their past. Not the cover up story, the real deal. My question is why on earth would anyone wish a group such as this to have any more say on how ANY country is run? They are morally and spiritually bankrupt, however they do seem to have rather a lot of money to throw around. I just dont need their input or their money. I know how they collect it.
Maybe a good suggestion to get the NZ tax authorities to investigate the money. Turn over a few stones and find out the TRUTH about Exclusive Brethren. Perhaps then, you would not be asking such a question.