Honesty,
I understand your unrelenting bias but to be really "honest" you have to admit that there is a difference between advocating that something should be "most" important to one's life and advocating that nothing else is important at all. True, Witnesses believe their faith should be most important, but it is also true that Witnesses are encouraged to be well-rounded and that their lives are spent in a variety of activities, many of them not having anything to do with theocratic activities or Witnesses' faith.
All that the counsel in the brochure is stating is that some Witness youths might have the idea that their faith is on trial or might think it is a situation to highlight their theocratic activity, the way they would do in a part at a convention. (As we know, those parts are meant to focus on a person's theocratic activity but one has to be naive to assume that such persons don't have other interests or don't spend some of their time in recreation or whatever.)
This reminder in the Child Custody brochure is only that, a reminder, to let them know that they should discuss all of their interests and activity, so that a court, the judge, can get a more accurate picture of their daily life. They are not being asked to make up anything or create a false identity. They can represent their life accurately, that is dedicated to being a Christian, but otherwise they are more or less normal in that they have other interests and they spend their time in a variety of activities.
-Eduardo