Crew member visa is for pilots and crew members of foreign airlines to fly into the US, for example an Air Canada flight operating into the US. The US is different in the respect that they require a crew visa for all foreign crews, including those from countries that belong to the Visa Waiver Program. Their take on it is that you are "working" within the borders of the US, therefore you require a visa.
Having worked for a Canadian airline for 7 years flying into the US with no visa of any kind, I would strongly disagree with your statement.