Why does the headline in the japan times and mail call the senate vote a "declaration of war"?

Believed the Senate's decision was an attack on the Japanese people.

The headline is referring to the passage of the Immigration Act of 1924 which placed quotas on immigration and ended immigration from Asian countries. 

The Senate act, Johnson-Reed Act or the Immigration Act of 1924, reduced European immigration with quotas and restricted immigration from places where the people were ineligible to gain US citizenship. The Supreme Court deemed Asian people, including the Japanese, unable to obtain US citizenship and therefore the act ended Japanese immigration to the US. The Japanese, who had been friends and allies to the US, took this as an insult to their people.