There are people way more qualified than me to answer your questions
Precisely. Why don't you contact Mito Paz at Green Reef or Billie Leslie at Tuff-e-Nuff for an authoritative explanation from someone who knows and understands what the issues are?
As to why people can't do whatever they want with property they own, the answer is simply that it isn't in the public's best interests and a political decision was made long ago that there would be restrictions placed. This general policy must have been well known to the purchasers of that property, as it's standard in any country that I've ever visited. The detail of those restrictions depends on local circumstances, as in any other country.
As to why the SBB area is particularly sensitive, ask the gentlemen above. But a simple glance at a map shows that it's right on top of Hol Chan and it is disingenuous to hold out that there won't be a significant effect.
Why don't you attend one of these meetings, listen to the arguments and watch whatever information they screen, and ask the acknowledged local experts your questions? They are not rabble-rousing special-interest group meetings, but are intended to inform the general public. Yesterday's was attended by our Minister for Tourism, no less, not pontificating from the high table but sitting in the audience and listening/watching with the rest of us.
Your final point. It is not up to this group or any other to develop or propose commercial ventures that any individual might consider. It is merely to prevent an initiative by any individual or business that seems inappropriate and against the public interest.