technically they are all supposed to be public.
that does not mean that the hotels won't try and stop people, especially who appear not to be tourists, from entering or forcing people to pay for access. also in a recent thread it was pointed out to me that the hotels do not have to give access thru their property.
i've entered beaches at all-inclusives, walking along the water, without any major incident although occasionally the guards, sometimes armed, have tried to stop me....unsuccessfully. i can only imagine that many of the locals might be intimidated, as portrayed in the video clip.