This is an ongoing problem/issue. You first need to visit the language sub-forum for your country and see if there is a discussion about what should be landmarked. If not start one. In the US a recent discussion decided (or mostly decided) that landmarks should be limited to parks, schools, hospitals, gas stations, Public parking lots (not just ones attached to a building but ones where the public is invited to park either for free or for a fee). And a few significant government buildings such as police, and post offices. I've probably missed a couple but you should get the idea. The thought is that except for parks which are green, landmarks or POI's merge together in the client, and POI's inside of larger POI's don't show at all, except for the names that appear to be just floating in the larger blob of the larger or conjoining POI's.
Thus the decision/consensus was to limit POI's and even request Waze cut down on the list of available POI's. But the Wiki has yet to be updated so it can be hard to enforce at times.
Personally I think that mess in your linked map is a mess and a prime example of why too many landmarks or POI's are a problem. I would highly recommend finding your country's forum and if there isn't a discussion about the topic, start one. Get a screen shot from the client of the same area as well to show how useless to many POI's become. Also at least so far, mapping POI's does nothing for searching for the locations, search results come from outside services (Bing, Yelp, Google, 4Square etc...) not from the POI's placed by editors.
I hope you aren't confused by the way I bounced back and forth between POI and Landmark, in this discussion they are the same thing, in the US discussions they seem to mostly get called landmarks.