As the chef referred to on the article, most Japanese just think independence day one of holidays. National holidays in Japan has become a meaningless since enactment of 'Happy Monday' Law, which moves some holidays to Mondays on purpose of ensuring the number of actual holidays.
Independence day also became looked down on except by conservative people. Rather than holidays, Saint Valentine's Day and Christmas Day are widely taken up in Japan. On these days, I often feel as if they were 'Independence days' in terms of lacking a girlfriend.