This. A lot of westerners think of it as Chinese New Year because the way they found out about the holiday was through the way Chinese communities celebrate it. Korea and other countries that celebrate it don't have as big of a presence in the west, at least not historically. So the holiday became associated with China in the eyes of the west. Japan might have been able to offer another perspective, but Japan doesn't really celebrate it.
Japan used to celebrate it before the Meiji Restoration. That last era Japan officially celebrated Lunar New Year was during the Edo Period.