Is there any more background about this campaign?
In a holistic view, I can't see designation of Country Park can help bird/birding activities on the island as the core area of birdwatching is village or residential zone which is difficult to rezone as Country Park.
Also, please be aware wild camping is prohibited in Country Park - designation of Country Park would make the camping site from unofficial to illegal. Of course you can ask for a proper camping site on Po Toi, but I am afraid it would trigger more infrastructure on the island.
Country Park can help preserve the habitat intact but it would also draw more visitor and therefore more tourist and safety facilities. Conservation is not always compatible with eco-tourism, making the island high profile or an official country park may trigger side effect.