I myself am reading quite a bit of meaning into the conspicuous avoidance of the characters "tian", "an", and "men" throughout both ads.
The melon ad is fairly defiant, though, in a classy kind of way. If I were a betting man, I'd take the other side. Preserving absolute rule of law in Hong Kong is as doomed as the Taiwan independence movement. The Chinese anschluss seems unstoppable.
The complete hidden message is actually a bit longer:
No way that's an accident.
In context, it likely isn't straining. If he desired to simply declare an end to violence, he could have done so in a less tortured graphical format.