熱烈慶祝, meaning warmest celebration in Chinese, is a usage that has been prevalent in mainland China’s media and streets for long, especially for such occasions as celebrating the opening of National Assembly or anniversary of Communist Party founding.
It is obvious that HK is gradually adopting the “communist” language usage, which is sheer propaganda. What is more frustrating is the slogan. While 15 years on after the return of Hong Kong to China, there is nothing to celebrate, the slogan tells the opposite of how people here feel. This is sheer lie and flattery to the power in “motherland’.
And put in up here in the park, public space? That is meant to draw the ire of people here.