For many of those people, it's not a risk of homelessness but rather that they would have to rent someplace outside the favela at a much higher price, one they may be able to barely afford. Sort of like in the US, where zoning/building don't generally make people homeless but instead put a person into the situation of the favela dweller who has the option to rent while paying a large portion of their income, except without the option to build their own sub-code housing.