It does mean that it is important for them, but more that they want to involve the media in what they are doing, not to rely on it for information.
to "factor in" (It is a phrasal verb) means to take something into account or make something an important part of the process when doing something such as making a decision or plan.
For instance, the Virginia shooter planned his shooting in such a way that it would have the greatest impact in the media. In that way he "factored in" the amount of media attention he would get.