Jan 14: WHO repeats China's claim that Covid-19 does not spread human-to-human, despite data from Taiwan demonstrating otherwise.
Jan 21: WHO repeats assertion that Covid-19 poses no world health threat.
Feb 3: WHO criticizes US for instituting travel bans against China, calling them "unnecessary" as China has the outbreak "well contained".
Mar 3: WHO, citing data from China, says Covid spreads "much less efficiently than the flu", and that all but 1% of carriers have symptoms. This statement is immediately criticized as false by public health officials in South Korea, Japan, and elsewhere.
Mar 11: WHO finally declares Covid a pandemic, and admits it is highly infectious.
I don't believe you realize what, in epidemiological terms, the phrase "community spread" means. It is the point at which there are significant numbers of cases which cannot be traced to an origin. It is a basic staple of epidemiology that, once community spread has occurred, resources should be focused on community mitigation, as containment is no longer possible.
New Zealand never experienced community spread. The United States -- along with nations such as Italy -- not only experienced community spread, but did so before China and the WHO was even admitting there was a problem.