I’ve finaly managed to find (unofficial) explanation and it goes like this: once you publish your island to public and list it, it does not mean that your island will be visible (browsable, discoverable) by anyone. Selection of the islands that will be shown to players is secret ie. it is not known what makes some islands presented to the public and some others not.
Maybe it worked for creative 1.0 for someone who spent few hours throwing things around and then hoping that creation will be shown to others but I can not believe that anyone in his right mind would go through buggy editor with more non-working features than working, through programing language that is as confuscated as possible and still offers only a fraction of flexibility and spend weeks or months of effort just for an UNKNOWN CHANCE to be ever shown to public. Someone please pinch me because I can not belive that this is how it’s supposed to work.
Imagine creating a game and publishing it but you never know if players will ever be able to see it.