People use the word politics in two different ways.
1) Some people think it just means that bunch of stuff that the politicians and political parties fight over. To them, to make something political seems to be, at best, to create unnecessary argument and, at worst, an attempt by external powers to impose their will over it.
2) I, on the other hand, regard "politics" as an extremely positive and optimistic term, more or less synonymous with the word "freedom". Both "politics" and "freedom" are a state of being able to reflect critically on something so as to open up the possibility of acting on it to change it.
To politicize something, then, is to start the process of looking at it criticially. Asking whether it has to be the way it is. What forces make it the way it is, and what forces make us see it the way we currently see it. Politicization creates a new space for action.