I would say this applies to adults too. These hermeneutical problems are all too typical in sermons and adult books.
Here is an excerpt from Hermeneutics and Children's Curriculum by John Walton
...I have identified five basic fallacies that appear repeatedly:
1. Promotion of the Trivial: The lesson is based on what is a passing comment in the text (Josh 9:13, they did not consult the Lord), a casual observation about the text (Moses persevered in going back before Pharaoh over and over) or even a deduction supplied in the text (Joshua and Caleb were brave and strong). The Bible is not being properly taught if we are teaching virtues that the text does not have in focus in that passage. We would like children to be virtuous, but we dare not teach virtues rather than the Bible. The plague narratives are not teaching perseverance nor is the feeding of the multitude teaching sharing (as done by the little boy in one of the accounts).
2. Illegitimate extrapolation: The lesson is improperly expanded from a specific situation to all general situations (God helped Moses do a hard thing, so God will help you do a hard thing. But the hard thing Moses was doing was something commanded by God whereas in the lesson the hard thing becomes anything the child wants to achieve). In these cases what the text is teaching is passed by in favor of what the curriculum wants to teach and biblical authority is neglected.
3. Reading Between the Lines: This occurs when teachers or students are asked to analyze what the characters are thinking, speculate on their motives, or fill in details of the plot that the story does not give. When such speculations become the center of the lesson, the authority of the biblical teaching is lost because the teaching is centered on what the reader provided.
4. Missing important nuance: This occurs when the curriculum pinpoints an appropriate lesson but misses a connection that should be made to drive the point home accurately. It is not enough, for instance to say that God wants us to keep his rules—it is important to realize that God has given us a sense of who he is and how we ought to respond in our lives. It is not just an issue of obeying rules—God wants us to know him and respond to him by following in his ways and being like him.
5. Focus on people rather than God: The Bible is God’s revelation of himself and its message and teaching is largely based on what it tells us about God. This is particularly true of narrative (stories). While we are drawn to observe the people in the stories, we cannot forget that the stories are intended to teach us about God more than about people. If in the end, the final point is “We should/shouldn’t be like X (= some biblical character)” there is probably a problem unless the “X” is Jesus or God. Better is “we can learn through X’s story that God . . .”
If we are negligent of sound hermeneutics when we teach Bible to children, should it be any wonder that when they get into youth groups, Bible studies and become adults in the church, that they do not know how to derive the authoritative teaching from the text?
We all have a working hermeneutic, even though most have never taken a course. Where do we learn it? We learn it from those we respect. For many people this means that they learn their hermeneutics from their Sunday school teachers. Teachers in turn teach what is put into their hands. Perhaps we ought to be more attentive how Sunday school curriculum is teaching our children to find the authoritative teaching of God in the stories.
Personally, in our family, we highly recommend the curriculum from Children Desiring God.