because you do not cook cake? while ciasto=dough can be used to make things that are then boiled (pierogi), we never "gotujemy ciasto". We either prepare / make it, or when ciasto= cake we bake= pieczemy.

gotować = boiling and you don't usually boil cakes, do you? ;) Only secondary meaning of this verb is general cooking, but it only encompasses preparing actual meals(as opposed to preparing sweets/desserts/cakes and so on), because meals usually involve some boiling(even instant noodles like Vifon require boiled water).

Ciasto się robi(or piecze - bake), most other non-meals are too made(robić) or sometimes prepared(przygotowywać).

Not really, there are types of cakes every Pole would call "ciasto" – we are differentiating the two, but for native English speakers apparently "ciasto" and "tort" are the same thing(i.e. a cake). ;-)