I don't know how many of you agree with me, but I just have to say that is sort of bothers me--if not completely pisses me off-- when someone sees me reading an Animorphs book, or talking about Animorphs and say, "Dude, you're eighteen. Why are you reading a kids series?"
I did not have this problem as I hid the fact I was still reading those books after elementary school to everyone except one friend (my "bff" at the time, and she did tease me!)
Back to topic: Why are those books not for kids or for kids.
First you would probably need to separate the series in 2 parts since it evolved as the readers evolved and it really got darker towards book 40 something and then you would need to define "kids".
Are you talking about 8 to 10 kids ? Or 10 to 12 kids? Or...?
You say that the characters are "children" around 13, but at that age many children are considered teens more than children.
To me those books are well suited for young people around the age of 10 (start of the series) to 13(end of the series) so that I cannot really argue your position that those books aren't for "kids" (if kids means young teens).
I'll add some points to your list "why they are for kids(=young teens)":
7) The
shortness of sentences which is something that I actually really appreciate. A lot. (
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8 ) The simplicity of the text. Simple words are used, no long descriptions full of complicated adjectives, sentences are mostly turned towards action rather than description...
9) The plot itself is mostly action oriented, and this despite Cassie's "whining moments".
10) The violence may not be a point in favor but is definitely not a point against.
First because the ones which typically get hurt (at the start of the series) are the yeerks and those yeerks are firstly introduced as evil beings.
Second because until late in the series, there are no real strong consequences on the main characters, the ones the reader gets attached to (apart from Tobias, but as it happens in the very first book, which is not even narrated by him, it is hard to empathized). Often the books conclude with them gathering around food or some group activity.
Besides the perception the reader gets of the "evil aliens" slowly evolves with the books in a carefully planned way (at least at the start of the series) and young teens are old enough to be receptive to the moral conflicts introduced by the author. Book 19 does a really good job at handling the motivations of each specie and at giving a "human face" to the enemy. I think that at least by the age of 12 an average teen should be able to understand the moral issues this book brings.
11) The humor. Book 14 cracked me up when I was 9. I laughed from the start to the end. Not something that would work on me anymore. In general the humor is adapted to young teens (except Ax's joke about the symmetry of the shelves, this one is for all ages).
A big point that I'd like to make here, even if not really in a list because it would cross several list points is that the grey vs black and white, the moral issues etc... Are the main reason why those books are really good for young teens and why they may seem dull to adults.
Because when you are 11/12 you start rebelling against authority (of adults), or at least questioning it, you create your own identity and you start questioning some of the knowledge and moral you were given so far by your family, school...
The kids in animorphs do the same, they discover the shades of grey, they cannot trust adults, and with the battle for earth they discover new/hidden parts of themselves... All those things echo to what the readers feel, and maybe help him raise questions as well (book 19,THC,...).
The turn off part for older teens is that they generally already went over this. They know adults can be dicks, life is not all white and black,... Let's say that when you are 18, you won't be attracted to animorphs for its intellectual challenges since it mostly addresses issues you should, by that age, have already thought of (in class, with your friends, or by yourself)