In my whole life, I just know now the other means of squatting. After searching Google for a while, it seems that squatters often decorated the building they squat. In my opinion, squatting is wrong.
Well, it is wrong because you settle in a property without proper law permissions or paying rents. You break the law because the buildings would otherwise be used by others who are willing to pay to live in the building where you settle in.
Obviously, this doing is also justifiable because when a property is abandoned, it is prone to obsolescent and become useless, I think. Although my way of thinking may be flawed, but letting people squat abandoned buildings actually is a good deed, given it’s viewed from other point of view.
Otherwise, it’s up to the local government how to deal with these squatters.