Poor choice of words. Adams is from New Zealand. Right next door is Australia. This reminded me of this 2009 clip from an Australian reunion special of the show "Hey Hey It's Saturday". One of the performances was a group doing Jackson 5 in blackface. They had done it numerous times before.
http://youtu.be/qEtjaZ8ZuNUAmerican musician, Harry Connick Jr, was a guest judge and was visible disturbed by the performance.
It got a little flack in Australia, but mostly just highlighted the difference in cultural acceptance of black face. Part of the reason it didn't outrage more Australians is because the negativity surrounding black face is much greater in America. It was a popular in American minstrel shows in the late 1800s/early 1900s. It played on a lot of American stereotypes like plantation workers and "dandified coons". It ended during the American Civil Rights movement of the 1960s when Americans started to embrace and celebrate African Culture on a wider scale.
The baggage surrounding blackface is much greater here. In Australia, easily less than 1% of the population is black. Actually, they have almost zero African-Americans living there - given that "African-
American" refers to Americans of African descent and all. The African-Australians they do have mostly came in in the 1980s and 2000s. While Australia dabbled in slavery with Aboriginal people, they have almost no personal context for why Americans react in horror at blackface. To those dancers, they thought what they were doing was in good fun and harmless.
I'm not saying it's the same thing, but Adams referring to a couple black people as monkeys was likely just as harmless. He probably doesn't have it deeply embedded in him that saying such a thing is racist in America. That's not to say that blackface/calling black people monkeys isn't racist everywhere, but the cultural awareness isn't the same globally. I'm sure if a black American visited Australia or New Zealand, they'd potentially encounter what could be called racism here, but it would be a racism rooted in misunderstanding as opposed to deep-seeded hatred. My guess was Adams just called them quick little monkeys referring to how quick and pesky they are and was mildly oblivious to how offensive that comment comes across in America.