Since the housing crisis is becoming a grave concern for many cities, local governments believe reducing greenery for more buildings is the right choice. From my point of view, going to such extreme lengths is not the right course of action.
Firstly, it is understandable why some believe that park land is less crucial than residential development. As the population for every city is massively growing, be it birth rate or immigration there are not enough residential areas to keep all these people. So the easiest course of action seems to be reconstructing parks, green and natural lands for more buildings, which in fact will help solve the problem. In seemingly small cities the problem is solved exactly that way, you can see towering buildings in the elevated areas such as hills.
Though, robbing the city of its already small amount of greenery is quite wrong if you ask me. Living in the city already comes with several health risk factors because of pollution, confined spaces and much more, so having a natural habitat to take a breath of fresh air is important to keep a considerable amount of people healthy. There are other ways of making more space for people, like reconstructing old buildings and streets, making them more accessible and even keeping the values of the city without putting huge buildings in places that they do not fit in.
In conclusion, though it is understandable why the governments would think that reassigning park land for residential development is the right choice, I would not agree and say that there are other ways of solving the problem.