What do 18th-19th Century american whalers have to do with whaling in Japan? I was talking about modern commercial whaling which for Japan started in the 20th century and after WWII was given a major push by the US as whale meat was a cheap alternative to beef in the post-war period.
However since you did bring them up, it does bring in question the whole cultural argument. Much of early American culture revolved around whaling as there were many coastal towns on both sides of the country whose existence lay in whaling. Also one of our most famous literary classics, Moby Dick, is about whaling!