Blast aka Bill Gray

The Haka is performed by many New Zealanders and has become an integral part of New Zealand's sporting culture.

As part of New Zealand's heritage, the Haka has a special place in the social interaction and the feeling of belonging to New Zealand. It embraces the origins of New Zealand as a Nation and unites both Maori and Pakeha in a common bond that sets Aotearoa apart from most other nations.

The Haka is much more than just a dance of war. In Wikipedia the haka is described...

Today, haka constitute an integral part of formal or official welcome ceremonies for distinguished visitors or foreign dignitaries, serving to impart a sense of the importance of the occasion.

and also quoted...

Sports teams who perform a haka before international matches do so not only as a reflection of the importance of the game that is about to be played but also to motivate themselves and their supporters to greater efforts; indirectly then, as in days of old on the Māori battlefield, they are paying a compliment to the perceived skills of their opponents.

Although there is no requirement for the opposition teams to act in any way, the fact that people may choose to refuse to show respect to the Haka is showing their ignorance rather than anything else.

If you are interested in more visit The Haka Feature