When a new culture enters a civilization that new culture then becomes dominant. This seems to happen time and time again. Really is it anyone's fault? The new culture many times has one major thing up on it: It's new. It is something different than what the people are used to. Having the newer nicer toys is only part of human nature.
What makes Westernization the big bad guy is that it has had a reputation of being forceful of making people conform to their ways. There are countless examples of the western culture coming into a new and uncharted place and forcing the people to live their life the way that the new culture thinks is best. Hawaii was unfortunately no exception to that. When the missionaries came in they were not quite as forceful as they had been with some other cultures however when Queen Kaahumanu converted to Christianity shortly after. She then influenced her son whom she was regent to while he was a young king to convert to Christianity and make all traditional Hawaiian beliefs illegal. That included the Hula. She also put into law that they natives had to start wearing clothing. It wasn't until 1839 after her death that the King lifted the ban on the traditional Hawaiian beliefs and allowed the Hawaiians to worship as they wished.
Not to sound like I am Christian bashing here, the missionaries did do many things to help the people such as forming a Hawaiian alphabet. The unfortunate side effect is that the people have lost some of their original culture. They also inadvertently caught many of the diseases such as the measles which the people had no immunities for, so the natives were dropping off like flies.
Just because a culture is different does not mean it is not as important or that it is wrong. It's just different. A modern day example is the Muslim culture. Leaving the fundamentalism aside, the culture isn't necessarily bad. It's just different. Women who are from the western culture may not understand that covering one's self is not an act of inferiority for the women of this culture. To them it is seen as covering up themselves so that the only person who can see the "precious jewel" that is them is their husband.
The Hawaiian culture is so much more than Hula dancers dancing at a hotel show. Or a beach lined with hotels. It is so much more. It is a culture that reveres nature, o'hana (family) and a rich history. None of which should be forgotten.