I dunno. I think their explanation fits:
"It's important that licensees when conducting there business and engaging with consumers are conscious of the fact that not everybody is like them, that different people have different cultural understandings and the way conducting oneself can have a negative impact on a person."
However, the thing that really makes me side with the REA is that I looked up the course. It's a 1.5 hour module. I'm sorry but if you go to court because you want to be a real estate agent but don't want to do a 1.5 hour module on cultural diversity... well then you're probably the person that needs it the most.
1/4 of NZers weren't born here, and 1/5 are Māori, so it seems like a valuable use of time for an old white lady wanting to work with the public in a regulated profession.